Fabrication and characterization of cobalt- and copper-doped mesoporous borate bioactive glasses for potential applications in tissue engineering

Developing novel compositions of bioactive glasses (BGs) is key for accelerating tissue repair and regeneration. In this work, we developed a series of cobalt (Co)- and copper (Cu)-doped mesoporous bioactive glasses (MBGs) based on borate 13-93B3 composition using nitrate precursors. We took benefit from data science algorithms to predict and assess the physico-chemical and biological properties of the samples. The results showed that the presence of the dopants (Co and Cu) in the MBGs could change the glass transition temperature (Tg) (from 773 to 539 °C), the zeta potential (from -12 to -43 mV), and surface area (from 54 to 194 m2/g). However, the presence of 2.5 mol% of dopants in the composition led to just a slight decrease in their bioactivity. In vitro biocompatibility assays confirmed that all the glass samples were biocompatible. Furthermore, the doped MBGs exhibited potent antibacterial activity against both Gram-positive and Gram-negative bacteria. In addition, these glasses could induce the mobility of human umbilical vein endothelial cells (HUVECs) and enhance new blood vessel formation in ovo. According to the obtained data, it can be stated that this type of doped borate MBGs held great promise in tissue engineering applications

Enzymatic Mechanisms Involved in Evasion of Fungi to the Oxidative Stress: Focus on Scedosporium apiospermum

The airways of patients with cystic fibrosis (CF) are frequently colonized by various filamentous fungi, mainly Aspergillus fumigatus and Scedosporium species. To establish within the respiratory tract and cause an infection, these opportunistic fungi express pathogenic factors allowing adherence to the host tissues, uptake of extracellular iron, or evasion to the host immune response. During the colonization process, inhaled conidia and the subsequent hyphae are exposed to reactive oxygen species (ROS) and reactive nitrogen species (RNS) released by phagocytic cells, which cause in the fungal cells an oxidative stress and a nitrosative stress, respectively. To cope with these constraints, fungal pathogens have developed various mechanisms that protect the fungus against ROS and RNS, including enzymatic antioxidant systems. In this review, we summarize the different works performed on ROS- and RNS-detoxifying enzymes in fungi commonly encountered in the airways of CF patients and highlight their role in pathogenesis of the airway colonization or respiratory infections. The potential of these enzymes as serodiagnostic tools is also emphasized. In addition, taking advantage of the recent availability of the whole genome sequence of S. apiospermum, we identified the various genes encoding ROS- and RNS-detoxifying enzymes, which pave the way for future investigations on the role of these enzymes in pathogenesis of these emerging species since they may constitute new therapeutics targets

Evolution of the 3D plastic anisotropy of HCP metals: Experiments and modeling

International audienceA two-surface, pressure-insensitive plasticity model is further developed to represent the mechanical response of hexagonal close packed metals. The model describes the 3D plastic anisotropy of a material, the tension–compression asymmetry, and the consistent evolution upon straining of both the net anisotropy and the asymmetry. The model may be viewed as a reduced order quasi-crystal plasticity model whereby the two activation surfaces represent glide- and twinning-dominated flow. The two-surface formulation enables to represent independent, yet coupled, hardening laws in terms of effective plastic strains accumulated on either generic deformation system. Application of the model to a discriminating data set assembled for a magnesium alloy thick plate illustrates the capabilities and versatility of the modeling approach

Analyses of black fungi by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS): species-level identification of clinical isolates of Exophiala dermatitidis

Nahid Kondori1,*, Marcel Erhard2, Christina Welinder-Olsson1, Marizeth Groenewald3, Gerard Verkley3 and Edward R. B. Moore1,41Department of Infectious Diseases, Sahlgrenska Academy of the University of Gothenburg, SE-40234 Gothenburg, Sweden2RIPAC-LABOR GmbH, D-14476 Potsdam, Germany3Centraalbureau voor Schimmelcultures (CBS), CBS-KNAW Fungal Biodiversity Centre, 3584 CT Utrecht, Netherlands4Culture Collection University of Gothenburg, Sahlgrenska Academy of the University of Gothenburg, SE-40234 Gothenburg, Sweden↵*Corresponding author: Department of Infectious Diseases, University of Gothenburg, Box 7193, 40234 Gothenburg, Sweden. Tel: +46-31-342-4226; Fax: +46-31-342-4975; E-mail: nahid.kondori{at}microbio.gu.seRevision received July 8, 2014.Accepted November 3, 2014.AbstractConventional mycological identifications based on the recognition of morphological characteristics can be problematic. A relatively new methodology applicable for the identification of microorganisms is based on the exploitation of taxon- specific mass patterns recorded from abundant cell proteins directly from whole-cell preparations, using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). This study reports the application of MALDI-TOF MS for the differentiation and identifications of black yeasts, isolated from the respiratory tracts of patients with cystic fibrosis (CF). Initial phenotypic and DNA sequence-based analyses identified these isolates to be Exophiala dermatitidis. The type strains of E. dermatitidis (CBS 207.35T) and other species of Exophiala were included in the MALDI-TOF MS analyses to establish the references for comparing the mass spectra of the clinical isolates of Exophiala. MALDI-TOF MS analyses exhibited extremely close relationships among the clinical isolates and with the spectra generated from the type strain of E. dermatitidis. The relationships observed between the E. dermatitidis strains from the MALDI-TOF MS profiling analyses were supported by DNA sequence-based analyses of the rRNA ITS1 and ITS2 regions. These data demonstrated the applicability of MALDI-TOF MS as a reliable, rapid and cost-effective method for the identification of isolates of E. dermatitidis and other clinically relevant fungi and yeasts that typically are difficult to identify by conventional methods.Exophiala dermatitidisfungiMALDI-TOF MSwhole-cell protein profiling© FEMS 2014. All rights reserved. For permissions, please e-mail: journals.permissions{at}oup.co

Modeling the 3D Plastic Anisotropy of a Magnesium Alloy Processed Using Severe Plastic Deformation

International audience9 10 The mechanical response of magnesium AZ31 processed 11 using severe plastic deformation is characterized using a 12 two-surface, pressure-insensitive plasticity model. The 13 model captures the 3D plastic anisotropy and the tension-14 compression asymmetry as the behavior evolves during 15 straining. The model may be viewed as a reduced-order 16 quasi-crystal plasticity model, whereby the two activation 17 surfaces represent glide-and twinning-dominated flow