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Two-dimensional molybdenum-disulfide (MoS₂) catalysts can achieve high catalytic activity for the hydrogen evolution reaction upon appropriate modification of their surface. The intrinsic inertness of the compound's basal planes can be overcome by either increasing the number of catalytically active edge sites or by enhancing the activity of the basal planes via a controlled creation of sulfur vacancies. Here, we report a novel method of activating the MoS₂ surface using swift heavy ion irradiation. The creation of nanometer-scale structures by an ion beam, in combination with the partial sulfur depletion of the basal planes, leads to a large increase of the number of low-coordinated Mo atoms, which can form bonds with adsorbing species. This results in a decreased onset potential for hydrogen evolution, as well as in a significant enhancement of the electrochemical current density by over 160% as compared to an identical but non-irradiated MoS₂ surface.

High resolution AFM imaging of swift heavy ion irradiated muscovite mica under grazing incidence provides detailed insight into the created nanostructure features. Swift heavy ions under grazing incidence form a complex track structure along the surface, which consists of a double track of nanohillocks at the impact site accompanied by a single, several 100 nm long protrusion. Detailed track studies by varying the irradiation parameters, i.e. the angle of incidence (0.2 degrees-2 degrees) and the kinetic energy of the impinging ions (23, 55, 75, 95 MeV) are presented. Moreover, the track formation in dependence of the sample temperature (between room temperature and 600 degrees C) and of the chemical composition (muscovite mica and fluorphlogopite mica) is studied.

The purpose of this work is to study the biological activity of Anastatica hierochuntica L., against nine bacterial strains responsible of urogenital infection (UTI) for women. The plant was collected from Tindouf region (Far Southwest Algerian). In this study we performed a phytochemical screening and evaluation of antibacterial activity of three macerates of two vegetative parts (seeds and stems) by two methods (disk and wells diffusion method). Given the results, it appears that macerates obtained were rich in bioactive phyto-constituents particularly the seed of the plant. They showed the presence of ten large chemical groups. The yield of aqueous, methanolic and etheric macerates of the seeds and stems were (5,1; 3,8), (5; 1,4) and (2; 0,95)% respectively. The antibiotic resistance profile of the bacterial strains tested showed an increased resistance against several antibiotics families. The evaluation of the antibacterial potential of macerates showed that methanolic and aqueous macerates of the seeds were more active against Gram-positive bacteria compared to Gram-negative bacteria. The preliminary results of our study, allowed us to predict that natural substances in the plant can be considered as an important source possess compounds with significant antibacterial and antioxidant properties, which suggests their application in the pharmaceutical industry. &nbsp

The long-term nutritional efficacy of a highly-pure-enriched-cellulose (HPEC) diet and its effects on lipid metabolism and oxidant/antioxidant status were investigated in obese offspring of streptozotocin-induced diabetic rats. Diabetes in pregnant rats was induced by intraperitoneal injection of streptozotocin on day 5 of gestation. Control pregnant rats were injected with citrate buffer. At weaning offspring of diabetic and control rats were fed HPEC or control diet, they were housed individually in metabolic cage for 2 months to investigate the nutritional efficacy of the diets. Consumption of HPEC diet decrease weight gain and energy intake, increase fecal weight and reduce lipid and protein digestibility; however, these diet had no effect on protein utilization, and nitrogen balance remained positive which confirms that HPEC diet had no significant long-term nutritional risks. Indeed for obese offspring from diabetic rats, these diet associated with high satiety promote weight loss, and provide reasonable glycemic control, these diet also lower blood lipids concentration and correct the imbalance of oxidant/antioxidant system. HPEC diet had a protective effect against long-term metabolic abnormalities associated with macrosomia.

International audience

The present study focused on the analysis of microbiological quality of various milk samples such as ultra-high temperature sterilized milk (UHT), melted cheese and yoghurt, obtained from dairy product factories in western Algeria. Hazards identification and development of a quality management standard for these subsidiaries evidenced that the sanitary quality was satisfactory. The result revealed detection of faecal origin contamination ‘total and fecal coliforms’ in both the yoghurt product and sample of melted cheese where the average content was(1.29±6.72-0.14±0.56 x 103cfu/g) and (0.14±0.6-0.022±0.275 x 103cfu/g) respectively. It is indicative that all samples were free from Staphylococcus aureus and Salmonella sp. The study demonstrated that prerequisite programs (PRP) will prevent the occurrence of microbiological hazards origin, which confirms the fact that hygiene measures are the best safety assurance. The hazard analysis of the production process of yoghurt and cheese allowed us to find out their causes, adoption of preventive measures for certain sensitive stages where hazards can be eliminated or reduced at acceptable levels, the determination of critical control points (CCP)and operational prerequisite programs ‘PRPo’, implementing critical limits, and monitoring plans. DOI: http://dx.doi.org/10.3329/mh.v3i1.19777 Microbes and Health, June 2014. 3(1): 21-24

The present study focused on the physico-chemical and bacteriological quality assessment of samples including ultra-high-temperature (UHT) sterilized milk, melted cheese and yoghurt, collected from dairy product factories in western Algeria. Hazards identification and development of a quality man-agement standard for these subsidiaries were established. The physico-chemical and bacteriological quality of products analyzed was satisfactory, with the exception of 20% of the samples of fruity yoghurts where the titrat-able acidity was relatively high 1.337 ± 0.143%. Prerequisite programs (PRP) established will prevent the occurrence of hazards microbiological origin, which confirms the fact that hygiene measures are the best safety assurance. The hazard analysis of the production process of yoghurt and cheese allowed us to determine their causes, preventive measures for certain sensitive stages where hazards can be eliminated or reduced to acceptable levels, the de-termination of critical points for mastery (CCP) and operational prerequisite programs (PRPo), establishing critical limits, and monitoring plans. Awareness actions and information on potential risks are essential for consumers.

Tetragonally structured barium titanate (BaTiO 3 ) single crystals were irradiated using 635 MeV 238 U + ions to fluences of 1 × 10 7 , 5 × 10 10 and 1.4 × 10 12 ions cm −2 at room temperature. Irradiated samples were characterized using ion channeling, X-ray diffraction, helium ion microscopy and transmission electron microscopy. The results show that the ion-entry spot on the surface has an amorphous core of up to ∼10 nm in diameter, surrounded by a strained lattice structure. Satellite-like defects around smaller cores are also observed and are attributed to the imperfect epitaxial recrystallization of thermal-spike-induced amorphization. The critical value of the electronic stopping power for creating observable amorphous cores is determined to be ∼22 keV nm −1 . Molecular dynamics simulations show an amorphous track of ∼1.2 nm in radius under thermal energy deposition at 5 keV nm −1 ; the radius increases to ∼4.5 nm at 20 keV nm −1 . A linear fit of the core diameter as a function of the square root of the energy deposition rate suggests a reduction in the diameter by an average of ∼8.4 nm due to thermal recrystallization if electron–phonon coupling efficiency of 100% is assumed. The simulation also reveals details of the bonding environments and shows different densities of the amorphous zones produced at different energy deposition rates.

International audience; An innovative experimental setup, PELIICAEN, allowing the modification of materials and the study of the effects induced by multiply charged ion beams at the nanoscale is presented. This ultra-high vacuum (below 5 × 10−10 mbar) apparatus is equipped with a focused ion beam column using multiply charged ions and a scanning electron microscope developed by Orsay Physics, as well as a scanning probe microscope. The dual beam approach coupled to the scanning probe microscope achieves nanometer scale in situ topological analysis of the surface modifications induced by the ion beams. Preliminary results using the different on-line characterization techniques to study the formation of nano-hillocks on silicon and mica substrates are presented to illustrate the performances of the setup

Distributed software systems change dynamically due to the evolution of their environment and/or requirements, their internal designing policies, and/or their specification bugs which must be fixed. Hence, checking system changes must be run continuously. Such systems are usually composed of distributed software entities (called peers) interacting with each other through message exchanges, and this is to fulfil a common goal. The goal is often specified by a conversation protocol (CP), i.e. sequences of sent messages. If there exists a set of peers implementing CP, then CP is said to be realisable. In this paper, we propose a stepwise approach for checking whether an evolution, i.e. adding and/or removing messages and/or peers, can be applied to a CP that was realisable before updating it.We define a set of correct evolution patterns and we suggest an algebra of CP evolution. Our approach ensures that CP evolution preserves the realisability condition.

International audience; Distributed software systems are often built by composing independent and autonomous peers with cross-organisational interaction and no centralised control. These peers can be administrated and executed by geographically distributed and autonomous companies. In a top-down design of distributed software systems, the peers' interaction is often described by a global specification called Conversation Protocol (CP) and one have to check its realisability i.e., whether there exists a set of peers implementing this CP. In dynamic environments, CP needs to be updated wrt. new environment changes and end-user interaction requirements. This paper tackles CP evolution such that its realisability must be preserved. We define some evolution patterns and prove that they ensure the realisability. We also show how our proposal can be supported by existing methods and tools based on refinement and theorem proving, using the event-B langage and RODIN development tools.

The composition of an annealed ternary system is examined by combined ion beam analysis (standard RBS & nuclear microprobe PIXE), SEM (morphology & EDS) and also with XRD to get the elemental composition and distribution over particular micro regions. The ternary system is built by the superposition of two metal layers, Gold and Copper respectively, both having 1200 Å in thickness, successively deposited on a (111) monocristalline silicon substrate. Then, the whole system is subjected to a vacuum heat treatment (at 400°C during 30 min). The enhanced interdiffusion and the arisen transformations are evidenced [8]. The investigations are particularly, emphasized on the induced Copper Silicide. A mapping of the elemental distribution, over restricted area is provided by micro-PIXE using the method of Dynamic Analysis as well as the corresponding Geo-PIXE II Software package. On the other hand, a special web network likewise is realized by performing several EDS punctual analysis, strictly focused on the formed phase site resulting in a well defined planar zoning of the elemental distribution.

Objective: The purpose of this work is to study the biological activity of Anastatica hierochuntica L., against nine bacterial strains responsible for women’s uro-genital infection (UGI).Methods: The plant was collected from Tindouf region (far southwest Algeria). In this study, we performed an evaluation of antibacterial activity of three macerates of two vegetative parts (seeds and stems) by two methods (disc and wells diffusion methods), with a description of the antibiotic resistance profile of isolated bacterial strains by antibiogram method.Results: According to the results, the antibiotic resistance profile of the tested bacterial strains showed an increased resistance against several antibiotics families. The evaluation of the antibacterial potential of macerates showed that methanolic and aqueous macerates of the seeds were more active against Gram-positive bacteria compared to Gram-negative bacteria.Conclusion: The preliminary results of this study allowed us to predict that natural substances in the plant can be considered as an important source to possess compounds with significant antibacterial properties and thus suggest their application in the pharmaceutical industry.

International audience; A novel form of ion-tracks, namely nanogrooves and hillocks, are observed on CaF2 after irradiation with xenon and lead ions of about 100 MeV kinetic energy. The irradiation is performed under grazing incidence (0.3°–3°) which forces the track to a region in close vicinity to the surface. Atomic force microscopy imaging of the impact sites with high spatial resolution reveals that the surface track consists in fact of three distinct parts: each swift heavy ion impacting on the CaF2 surface first opens a several 100 nm long groove bordered by a series of nanohillocks on both sides. The end of the groove is marked by a huge single hillock and the further penetration of the swift projectile into deeper layers of the target is accompanied by a single protrusion of several 100 nm in length slowly fading until the track vanishes.By comparing experimental data for various impact angles with results of a simulation, based on a three-dimensional version of the two-temperature-model (TTM), we are able to link the crater and hillock formation to sublimation and melting processes of CaF2 due to the local energy deposition by swift heavy ions.

Les infections de l’appareil urinaire sont courantes et parfois graves. Elles représentent un véritable problème de santé publique. Par ailleurs, l\'utilisation fréquente des antibiotiques pour le traitement de ces infections engendre un risque important de résistance bactérienne.C\'est pourquoi nous nous intéressons dans ce travail à l\'évaluation du pouvoir antibactérien, par la technique de diffusion en disque sur l’agar, de la gomme arabique d’Acacia tortilis de la région de Tindouf (Extrême Sud-Ouest Algérien) contre quelques souches bactériennes responsables d’infections urinaires basses et génitales chez la femme.Le profil d’antibiorésistance des souches bactériennes testées a révélé une résistance accrue vis-à-vis de l’Ampicilline et de l’Amoxicilline-acide clavulanique pour les Entérobactéries (Escherichia coli et Citrobacter sp), alors que les souches Staphylococcus aureus ont présenté une résistance à l’Ampicilline, à la Pénicilline et à l’Oxacilline.Le pouvoir antibactérien de l’extrait aqueux à base de la gomme arabique a montré que l’apparition des zones d’inhibition est proportionnellement liée à l’augmentation de la concentration de l’extrait aqueux (0,1; 0,25; 0,5 et 0,75g/ml). Cependant, les bactéries à Gram négatif possèdent une forte résistance par rapport à celles à Gram positif.Les résultats préliminaires de cette étude nous ont permis de prédire que l’extrait aqueux testé possède un effet antibactérien non négligeable, ce qui laisse prévoir leur application en médecine traditionnelle., Urinary tract infections are more common and sometimes serious which probably represent a real public health problem. Furthermore, frequent use of antibiotics for the treatment of these infections generates bacterial resistance.That is why we are interested in this study to evaluate the antibacterial activity, by the disc diffusion method on agar, of the Arabic gum of Acacia tortilis from the region of Tindouf (Algerian Far Southwest) against several bacterial strains responsible of genital and lower urinary tract infection for women.The antibiotic resistance profile of the bacterial strains tested showed an increased resistance against Ampicillin and Amoxicillin-clavulanic acid for Enterobacteriaceae (Escherichia coli and Citrobacter sp), whereas, S. aureus strains presented a resistance to Ampicillin, Penicillin and Oxacillin.The antibacterial activity of the aqueous extract based on Arabic gum showed that the inhibition zones were relatively proportional due to the increase of the aqueous extract concentration (0.1, 0.25, 0.5 and 0.75 g/ml). However, the Gram-negative bacteria have a high resistance compared to Gram positive bacteria.The preliminary results of this study allowed us to predict that the tested extract has a significant antibacterial effect, which suggests their use in traditional medicine.

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In this contribution we present new experimental results for swift heavy ion irradiation under grazing incidence. This particular collision geometry forces the track formation to a region close to the surface, sometimes visible as a chain of individual nanodots, whose length can be controlled by the angle of incidence. For irradiation of mica surfaces a new track form is observed.

It is generally admitted that the irradiation of crystalline materials with high-energy heavy ions often leads to the formation of highly defective or amorphous tracks. In the latter case, the amorphization process follows a single-ion-impact mechanism. However, recent results demonstrate that in certain circumstances crystalline-to-crystalline phase transitions can also occur. This is well illustrated with the case of pure zirconia which can undergo a transition from the monoclinic to the tetragonal phase with a kinetics characterized by a sigmoidal shape. The present study provides new evidence that this transformation is driven by a double-ion-impact mechanism. Another important finding is that the steepness of the sigmoid depends drastically on the amount of the electronic-energy loss: a small change in this parameter leads to a catastrophic modification of the kinetics of the phase transition.

To investigate possible beam guiding and current density enhancement properties for conical glass capillaries for MeV ions transmission measurements with well collimated ion beams of 1 MeV He+ and 71 MeV Xe 19+ were done. No guiding effect was observed and only decent enhancement factors e between 1 and 2 were measured and attributed to scattered particles. A 3D Monte Carlo simulation which is based on SRIM code was developed. The simulation reproduces the experimental results very well. This shows that the transmission properties of capillaries for MeV ion beams are governed by simple elastic scattering of the ions in the glass of the capillary. © 2014 Elsevier B.V. All rights reserved.

Single crystals of lithium fluoride were irradiated with 790 MeV Pb ions in the temperature range between 300 and 700 K. The creation of defects along the ion trajectory was studied using optical absorption spectroscopy and small-angle X-ray scattering (SAXS). Surprisingly, the track radius is not significantly influenced by the increase of irradiation temperature, but the ion-induced change of the electron density in the track decreases substantially.

It is well known that under swift heavy ion irradiation vitreous silica is subject to compaction as well as to plastic flow. The aim of this contribution is to demonstrate that both phenomena can be understood on the basis of the thermal spike concept and the fact that molten silica exhibits a density anomaly in the temperature range between 2000 and about 5000 K. It is found that the predicted values for ion-beam-induced compaction and the growth-rate for plastic flow are in reasonable agreement with the experimental data obtained previously.

In an attempt to better understand the mode of action of the antagonistic fungus Microsphaeropsis sp., the interaction between this fungus and Venturia inaequalis was studied, using both light and electron microscopy. Cytological observations indicated that the antagonistic interaction between the two fungi likely involves a sequence of events, including (i) attachment and local penetration of Microsphaeropsis sp. into V. inaequalis hyphae; (ii) induction of host structural response at sites of potential antagonist entry; (iii) alteration of host cytoplasm; and (iv) active multiplication of antagonistic cells in pathogen hyphae, leading to host cell breakdown and release of the antagonist. The interaction was investigated further by gold cytochemistry. The use of gold-complexed β-1,4-exoglucanase and wheat germ agglutinin/ovomucoid-gold complex to localize cellulosic β-1,4-glucans and chitin monomers, respectively, resulted in regular labeling of V. inaequalis cell walls. This finding supports other studies refuting the classification of ascomycetes as only a glucan-chitin group. At an advanced state of parasitism, the labeling pattern of cellulose and chitin, which clearly showed that the level of integrity of these compounds was affected, suggested the production of cellulolytic and chitinolytic enzymes by Microsphaeropsis sp. Wall appositions formed in V. inaequalis in response to the antagonist's attack contained both cellulose and chitin. However, penetration of this newly formed material frequently succeeded. This study provides the first detailed picture of the cytological events associated with mycoparasitism in V. inaequalis.