Amino acid composition,foaming, emulsifying properties and surface hydrophobicity of mustard protein isolate as affected by pH and NaCl

Amino acid composition, protein hydrophobicity, foaming and emulsifying properties of mustard protein isolate at pH 3, 5, 7 and in 0.05 and 0.1 m NaCl were studied. Glutamic (19.18 ± 0.30%) and aspartic (7.49 ± 0.11%) acids were the dominants. Foaming ability was enhanced by NaCl. Time to reach 75 mL foam was 23% higher in water than in NaCl. Drained volume after 10 min was concentration dependent and was the lowest in 0.05 and 0.1 m NaCl at protein concentration of 2.5% and 5%. The emulsifying properties were pH and concentration dependent, and the best results were obtained at pH 3, corresponding to the highest positive charge density of the protein surface. The highest emulsion stability (90.22 ± 3.52%) was obtained in 0.05 m NaCl and 5% protein concentration, whereas the lowest (63.00 ± 1.06%) was in water at all protein concentrations. Protein hydrophobicity was low and depended of pH but not of NaCl.     

后京都议定书时代的大都市:从手段到目的,从规划到激发

2008年,法国政府发起"后京都议定书时代大都市"和"未来都市巴黎"的研究,l'AUC事务所入选10家国际团队作为大巴黎研究项目的咨询顾问。本文展示了l'AUC事务所的方案及其他4个项目,分别针对当代规划、城市主义和建筑不同方面的主要问题:回收,生态城,紧凑和节点城市。     

Growth and characterization of hydroxyapatite nanorice on TiO2 nanofibers

Hydroxyapatite (HA) coating with nanoparticles like nanorice is fabricated on chemically pretreated titanium (Ti) surface, through an electrochemical deposition approach, for biomaterial applications. The Ti surface was chemically patterned with anatase TiO₂ nanofibers. These nanofibers were prepared by in situ oxidation of Ti foils in a concentrated solution of H₂O₂ and NaOH, followed by proton exchange and calcinations. Afterward, TiO₂ nanofibers on Ti substrate were coated with HA nanoparticles like nanorice. The obtained samples were annealed at high temperature to produce inter diffusion between TiO₂ and HA layers. The resultant layers were characterized by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), X-ray Diffraction (XRD), Infrared Spectroscopy (FTIR), corrosion tests in SBF solution, and Electron Probe Micro Analysis (EPMA). It was found that only Ti from the titanium substrate diffuses into the HA coating and a good corrosion resistance in simulated body fluid was obtained.     

Propriétés viscoélastiques à l'etat fondu de matériaux composites à base de fibres de cuir et de polyéthylène basse densité ou de copolymères d'ethylène. II. Etudes en balance rhéomètre

The investigation of molten state properties of composite materials based on leather fibres and low density polyethylene or ethylene copolymers is carried out on a rheometer balance. It confirms the proposed investigations based on fibre/matrix-interactions, on the influence of the charge, and on the nature of the matrix. Additionally, it is possible to obtain variations of the elastomeric component which is very important for the phase transformation.     

Evidence for the Involvement of Pleckstrin Homology Domain-Containing Proteins in the Transport of Enterocin DD14 (EntDD14); a Leaderless Two-Peptide Bacteriocin

Bacteriocins synthesis is initiated from an inactive precursor, which is composed of an N-terminal leader peptide attached to a C-terminal pro-peptide. However, leaderless bacteriocins (LLB) do not possess this N-terminal leader peptide nor undergo post-translational modifications. These atypical bacteriocins are observed to be immediately active after their translation in the cytoplasm. However, although considered to be simple, the biosynthetic pathway of LLB remains to be fully understood. Enterocin DD14 (EntDD14) is a two-peptide LLB produced by Enterococcus faecalis 14, which is a strain isolated from meconium. In silico analysis of DNA encoding EntDD14 located a cluster of 10 genes ddABCDEFGHIJ, where ddE and ddF encode the peculiar DdE and DdF proteins, carrying pleckstrin homology (PH) domains. These modules are quite common in Eucarya proteins and are known to be involved in intracellular signaling or cytoskeleton organization. To elucidate their role within the EntDD14 genetic determinants, we constructed deletion mutants of the ddE and ddF genes. As a result, the mutants were unable to export EntDD14 outside of the cytoplasm even though there was a clear expression of structural genes ddAB encoding EntDD14, and genes ddHIJ encoding an ABC transporter. Importantly, in these mutant strains (ΔddE and ΔddF), EntDD14 was detected by mass spectrometry in the intracellular soluble fraction exerting, upon its accumulation, a toxic effect on the producing strain as revealed by cell-counting and confocal microscopy analysis. Taken together, these results clearly indicate that PH domain-containing proteins, such as DdE and DdF, are involved in the transport of the leaderless two-peptide EntDD14.     

Prediction of the band profiles of the mixtures of the 1-indanol enantiomers from data acquired with the single racemic mixture

The adsorption isotherm data of R- and S-1-indanol and of their racemic mixture on cellulose tribenzoate were measured by frontal analysis. These data were then fitted to the Langmuir, the Bilangmuir, the Toth, and the Langmuir-Freundlich isotherm models. The single component data fitted well to both the Bilangmuir and the Toth models. Combined with the lumped pore diffusion model (POR) of chromatography, these isotherms were used to calculate overloaded elution profiles of the pure enantiomers. The calculated and the experimental profiles agree excellently in all cases if the former are derived from the Bilangmuir model. The competitive experimental data also gave excellent agreement with the Bilangmuir model. The simultaneous fit of all the data, for the single components and the racemic mixture, gave again superior agreement with the bilangmuir model. The overloaded elution profiles of samples of the racemic mixture calculated with the Bilangmuir isotherm model combined with the POR model of chromatography gave results in very good agreement with the experimental band profiles of large samples of the racemic mixture. This confirms that in numerous cases the whole set of competitive isotherms of two enantiomers can be derived from the experimental data obtained only with the racemic mixture.     

Adsorption of Cr(VI) on Stipa tenacissima L (Alfa): Characteristics,kinetics and thermodynamic studies

This study aims to remove ionic Cr(IV) from aqueous solution using Stipa tenacissima L as a biomass source. The Arabic name for the plant Stipa tenacissima L is HALFA (ALFA) ; it belongs to the category of biosorbents agro-industrial origin. Stipa tenacissima L is from the center of the province of Djelfa Algeria. This biomass was characterized by various analytical techniques such as scanning electron microscopy, energy dispersive spectroscopy and Fourier-transform infrared spectroscopy. In order to optimize the operating conditions for the determination of ions of Cr(VI), the initial concentration of Cr(VI) ions, temperature, pH of the solution and the solid/liquid ratio were individually studied. According to the results, a fix rate of about 90% was recorded. Optimum biosorption conditions were found to be pH ~1, C_o = 50 mg/L, R = 5 g/L and T = 296 K. It was found that biosorption of Cr(VI) ions onto biomass of Stipa tenacissima L was better suitable to Langmuir model. The correlation coefficients for the second-order kinetic model obtained were found to be 0.996 for all concentrations. These indicate that the biosorption system studied belongs to the second-order kinetic model. Thermodynamics parameters as enthalpy, entropy of system and free energy were evaluated, which confirms the feasibility of the process. An empirical modeling was performed by using a 2⁴ full factorial design, and the regression equation for adsorption chromium (VI) was determined from the data. The initial metal ion concentration has the most positive pronounced effect in increasing the chromium (VI) adsorption, whereas the pH and adsorbent dosage have the most negative effect on the process.     

Bioprospecting Antimicrobials from Lactiplantibacillus plantarum: Key Factors Underlying Its Probiotic Action

Lactiplantibacillus plantarum (L. plantarum) is a well-studied and versatile species of lactobacilli. It is found in several niches, including human mucosal surfaces, and it is largely employed in the food industry and boasts a millenary tradition of safe use, sharing a long-lasting relationship with humans. L. plantarum is generally recognised as safe and exhibits a strong probiotic character, so that several strains are commercialised as health-promoting supplements and functional food products. For these reasons, L. plantarum represents a valuable model to gain insight into the nature and mechanisms of antimicrobials as key factors underlying the probiotic action of health-promoting microbes. Probiotic antimicrobials can inhibit the growth of pathogens in the gut ensuring the intestinal homeostasis and contributing to the host health. Furthermore, they may be attractive alternatives to conventional antibiotics, holding potential in several biomedical applications. The aim of this review is to investigate the most relevant papers published in the last ten years, bioprospecting the antimicrobial activity of characterised probiotic L. plantarum strains. Specifically, it focuses on the different chemical nature, the action spectra and the mechanisms underlying the bioactivity of their antibacterial and antiviral agents. Emerging trends in postbiotics, some in vivo applications of L. plantarum antimicrobials, including strengths and limitations of their therapeutic potential, are addressed and discussed.     

An orchestration approach for unwanted Internet traffic identification

A simple examination of Internet traffic shows a wide mix of relevant and unwanted traffic. The latter is becoming increasingly harmful to network performance and service availability, while often consuming precious network and processing resources. Coordinated attacks, such as distributed denial-of-services (DDoS), large-scale scans, and worm outbreaks, occur in multiple networks simultaneously and become extremely difficult to detect using an individual detection engine. This paper presents the specification of a new orchestration-based approach to detect, and, as far as possible, to limit the actions of these coordinated attacks. Core to the proposal is a framework that coordinates the receiving of a multitude of alerts and events from detectors, evaluates this input to detect or prove the existence of anomalies, and consequently chooses the best action course. This framework is named Orchestration-oriented Anomaly Detection System (OADS). We also describe an OADS prototype implementation of the proposed infrastructure and analyze initial results obtained through experimentation with this prototype.