Metabolic fate of ochratoxin A as a coffee contaminant in a dynamic simulator of the human colon

Ochratoxin A (OTA) is a mycotoxin frequently encountered in coffee. The relevance of this contaminant in the colon upon digestion necessitates a study on its interaction with colon microbiota. Here, the fate of OTA during colon digestion was investigated using a dynamic simulator of the human gut. The influence of coffee as a food matrix was taken into account, as it may affect the colonic microbial ecosystem and, consequently, the fate of OTA. Biodegradation was followed by measuring OTA concentration over time, and by screening for several possible metabolites, using LC–ESI-MS and HRMS. The descending colon was found to be the main site of OTA biodegradation. Two metabolites, ochratoxin α and ochratoxin B, were identified, suggesting that biodegradation by gut microbiota is beneficial for the host, as they are considered less toxic than OTA. The extent of biodegradation was reduced in the presence of the coffee matrix, possibly due to competition for available carbon sources. Effects of OTA and the coffee matrix on the microbial ecosystem were contrasting. While OTA caused a specific, but lasting loss, of the beneficial species Lactobacillus reuteri, coffee temporarily altered the fermentation pattern towards lower ammonia and higher acetate and propionate production, likely due to its dietary fibre content.     

Development and characterization of thermosensitive hydrogels based on poly(N‐isopropylacrylamide) and calcium alginate

This work refers to the synthesis and characterization of thermosensitive hydrogels based on interpenetrating polymer networks (IPNs) of poly(N‐isopropylacrylamide) (PNIPAAm) and calcium alginate in the form of films. The influence of the crosslinking degree of PNIPAAm and alginate content on thermal, swelling, mechanical, and morphological properties of hydrogels is investigated in detail. Characterization of pure PNIPAAm hydrogels and IPN hydrogels was performed by FTIR, DSC, DMA, and SEM. In addition, the studies of equilibrium swelling behavior as well as swelling, deswelling, and reswelling kinetics are performed. The results obtained imply the benefits of synthesizing IPNs based on PNIPAAm and calcium alginate over pure PNIPAAm hydrogels. The presence of calcium alginate contributes to the improvement of mechanical properties, the deswelling rate of hydrogels, and the network porosity, without altering the thermosensitivity of PNIPAAm significantly. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Effect of spin finish on fiber/binder adhesion in chemically bonded nonwovens

The purpose of this study is to better understand the mechanisms governing the phenomena of fiber/matrix adhesion by controlling the fiber surface properties. This adhesion is evaluated by studying the micromechanical and thermodynamical behavior of the fiber/matrix interface. The complexity of the interactions at the interface requires a global approach that takes into account the chemistry, morphology, and mechanics. The thermodynamical affinity between the binder and fibers is evaluated by the wetting behavior, whereas the mechanical resistance of the fiber/matrix interface is characterized with the pull‐out test. Three distinct approaches are used to classify the different systems according to the nature of the binder and the fiber surface. It is found that there is better adhesion when the spin finish is removed from the fibers, revealing the surface roughness on which the latex can mechanically anchor. © 2006 Wiley Periodicals Inc. J Appl Polym Sci 102: 4092–4100, 2006     

Self‐Defensive Coating for Antibiotics Degradation—Atmospheric Pressure Chemical Vapor Deposition of Functional and Conformal Coatings for the Immobilization of Enzymes

Conformal epoxy‐rich coatings are synthesized by plasma initiated chain‐growth polymerization of glycidyl methacrylate via a newly developed Plasma initiated chemical vapor deposition method at atmospheric pressure to provide a functional platform for the immobilization of enzymes degrading antibiotics (laccase and β‐lactamase). In addition to enhance the enzymes activity duration and intensity, surface immobilization is also leading to enzyme structure rigidification, allowing them to endure mechanical stresses generated by a laminar water flow of 30 km h⁻¹, and this with no reduction of their enzymatic activity. Self‐defensive surface properties against microorganism's adhesion, preventing the enzyme alteration and improving the degradation performances, are obtained via surface saturation with Tween 20. The developed method is scaled up to high specific surface high‐density polyethy­lene biochips commonly used in water treatment, and shows self‐defensive abilities and particularly long lasting efficient degradation properties.     

Multicarrier CDMA techniques for future wideband wireless networks

In this paper, multicarrier techniques are considered in the context of the future wideband wireless networks. An overview of the different access schemes based on a combination of code division and multicarrier techniques, such as Multi-Carrier Code Division Multiple Access (MC-CDMA), Multi-Carrier Direct Sequence CDMA (MC-DS-CDMA) and Multi-Tone CDMA (MT-CDMA) is presented first. Afterwards, MC-CDMA systems are considered for the downlink of high rate cellular networks. The performance of different mono-user detection techniques are first analytically estimated and then compared with the help of Monte Carlo simulations for a Rayleigh channel. Simulation results on the performance of mono-user and multi-user detection techniques are also provided for Bad Urban (BU) Hilly Terrain (HT) and Vehicular UMTS channels. With regard to the channel coding, convolutional codes and turbo-codes are considered. Among others, a new linear detection technique named Global Minimum Mean Square Error Algorithm (GMMSE) is compared to multi-user Parallel Interference Cancellation detection technique. It is shown that GMMSE offers good performance especially for non-full load systems. Thus, the efficiency of MC-CDMA as a very promising multiple access and robust modulation scheme is successfully demonstrated for the downlink of the future wideband mobile networks.     

Control and Regulation of Integrated Mitochondrial Function in Metabolic and Transport Networks

The pattern of flux and concentration control coefficients in an integrated mitochondrial energetics model is examined by applying a generalized matrix method of control analysis to calculate control coefficients, as well as response coefficients The computational model of Cortassa et al. encompasses oxidative phosphorylation, the TCA cycle, and Ca²⁺ dynamics. Control of ATP synthesis, TCA cycle, and ANT fluxes were found to be distributed among various mitochondrial processes. Control is shared by processes associated with ATP/ADP production and transport, as well as by Ca²⁺ dynamics. The calculation also analyzed the control of the concentrations of key regulatory ions and metabolites (Ca²⁺, NADH, ADP). The approach we have used demonstrates how properties of integrated systems may be understood through applications of computational modeling and control analysis.     

Surface deposition and phase behavior of oppositely charged polyion-surfactant ion complexes. Delivery of silicone oil emulsions to hydrophobic and hydrophilic surfaces

The adsorption from mixed polyelectrolyte-surfactant solutions at hydrophobized silica surfaces was investigated by in situ null-ellipsometry, and compared to similar measurements for hydrophilic silica surfaces. Three synthetic cationic copolymers of varying hydrophobicity and one cationic hydroxyethyl cellulose were compared in mixtures with the anionic surfactant sodium dodecylsulfate (SDS) in the absence or presence of a dilute silicone oil emulsion. The adsorption behavior was mapped while stepwise increasing the concentration of SDS to a polyelectrolyte solution of constant concentration. The effect on the deposition of dilution of the bulk solution in contact with the surface was also investigated by gradual replacement of the bulk solution with 1 mM aqueous NaCl. An adsorbed layer remained after complete exchange of the polyelectrolyte/surfactant solution for aqueous NaCl. In most cases, there was a codeposition of silicone oil droplets, if such droplets were present in the formulation before dilution. The overall features of the deposition were similar at hydrophobic and hydrophilic surfaces, but there were also notable differences. SDS molecules adsorbed selectively at the hydrophobized silica surface, but not at the hydrophilic silica, which influenced the coadsorption of the cationic polymers. The largest amount of deposited material after dilution was found for hydrophilic silica and for the least-hydrophobic cationic polymers. For the least-hydrophobic polyions, no significant codeposition of silicone oil was detected at hydrophobized silica after dilution if the initial SDS concentration was high.     

Deletion of the Spata3 Gene Induces Sperm Alterations and In Vitro Hypofertility in Mice

Thanks to the analysis of an Interspecific Recombinant Congenic Strain (IRCS), we previously defined the Mafq1 quantitative trait locus as an interval on mouse Chromosome 1 associated with male hypofertility and ultrastructural abnormalities. We identified the Spermatogenesis associated protein 3 gene (Spata3 or Tsarg1) as a pertinent candidate within the Mafq1 locus and performed the CRISPR-Cas9 mediated complete deletion of the gene to investigate its function. Male mice deleted for Spata3 were normally fertile in vivo but exhibited a drastic reduction of efficiency in in vitro fertilization assays. Mobility parameters were normal but ultrastructural analyses revealed acrosome defects and an overabundance of lipids droplets in cytoplasmic remnants. The deletion of the Spata3 gene reproduces therefore partially the phenotype of the hypofertile IRCS strain.