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International audience; The alkylammonium halogenoferrate families are subjected to diverse studies according to their wide field application. However, these compounds show various transitions depending on the preparation process. In this paper, the [(C2H5)4N]FeCl4 compound was successfully synthesized using a slow evaporation solution growth method at room temperature. An optical absorption measurement confirms the semiconductor nature with a band gap around 2.95 eV. The X-ray powder diffraction (XRPD) data confirmed the formation of a single-phase with hexagonal-type structure. The differential scanning calorimetry (DSC) indicated that the [(C2H5)4N]FeCl4 compound undergoes eight reversible phase transitions between 193 and 443 K. At high temperature (T > 423 K) the plastic nature of the crystals was confirmed. Temperature-controlled X-ray diffraction reveals that the thermal expansion of the crystal structure is non homothetic in the (a,b) plane and along the c axis. The temperature dependence of the Raman spectra up to 443 K revealed specific reorientations and molecular displacements of the organic and inorganic components associated with the phase transitions. We aim to thermally stabilize the [(C2H5)4N]FeCl4 compound which has a band gap suitable for photocatalytic processes.

In the present study, we investigated the shell microstructures of the gastropod European abalone Haliotis tuberculata in order to clarify the complex spatial distribution of the different mineral phases. Our studies were carried out with a standardized methodology on thirty adult European abalone H. tuberculata (5-6 cm long) composed of 15 wild individuals and 15 individuals taken from the France Haliotis hatchery. The macroscopic (binocular) and microscopic observations coupled with Fourier Transform Infrared Spectroscopy (FTIR) and Raman vibrational analysis allowed to unambiguously detect, identify and localize calcite and aragonite. For the first time it has been shown that calcite is present in 100% of farmed and wild adult shell. The microstructural details of the calcite-aragonite interfaces were revealed by using both confocal micro-Raman mapping and Scanning Electron Microscopy (SEM) observations. Calcite zones are systematically found in the spherulitic layer without direct contact with the nacreous layer. The calcite area - nacreous layer interface is made of a thin spherulitic layer with variable thickness from a few micrometers to several millimeters. In order to contribute to a better understanding of the biomineralization process, a model explaining the hierarchical arrangement of the different phases of calcium carbonate is presented and discussed. Finally, it has been shown that these calcitic zones can be connected to each other within the shells and that their spatial distributions correspond to streaks perpendicular to the direction of length growth.

New antimicrobial polymer composite based on commercial polyurethane (PU) Laripur®LPR9020 and polymeric biocide polyhexamethylene guanidine hydrochloride (PHMG-Cl) has been prepared by solvent casting method. Modified PU films containing from 1 to 4 wt% of PHMG-Cl were characterized in terms of mechanical, thermal and surface properties, biocide release behavior, as well as antibacterial activity against Gram-negative (Escherichia coli) and Gram-positive (Bacillus subtilis) bacterial strains. The results of mechanical testing indicate that the introduction of PHMG-Cl did not cause noticeable changes in the tensile strength of PU films, but improved their elasticity by at least 20–30%. The surface of PU/PHMG-Cl films was found to possess significantly higher hydrophobicity than neat polymer that is manifested in sharply increased water contact angle value from 72° for neat PU to 95° for PU/PHMG-Cl (2%). According to thermogravimetric analysis data, PU/PHMG-Cl composites are thermally stable to at least 300 °C which indicate their availability for melt processing by common methods. The results of differential scanning calorimetry showed reduction of both glass transition and melting temperatures of PU by more than 7 °C when contained only 1% of PHMG-Cl. Gradual release of polymeric biocide from modified PU films into water has been detected spectrophotometrically. The total biocide release ratio was found to be in the range from 29% to 48% after 50 hours immersion, depending on its content in polymer composite. PU/PHMG-Cl films showed much lower leaching rate into physiological saline solution compared to pure water (from 10% to 21% after 50 hours), which may be caused by poor solubility of polymeric biocide in sodium chloride solutions. The study of antibacterial activity of modified PU films using both disc agar diffusion and contact methods indicate high efficacy against tested microorganisms when contained 3% of polymeric biocide. So, this approach, based on the modification of PU resin with polymeric biocide PHMG-Cl, has been discussed in terms of potential medical applications when biocide release system or contact active material are necessary.

International audience; Here, we report the first occurrence so far of cubic diamond and lonsdaleite in a siliceous breccia hosted in nickel laterite from the Tiébaghi mine, New Caledonia. Diamond and lonsdaleite polytype occurred as minerals in surficial formed siliceous rocks. The vibrational properties and the calculated elastic properties and electronic band structure of 3C-diamond and lonsdaleite were studied by micro-Raman spectroscopy and ab initio calculation. Our measured Raman spectra demonstrate the coexistence of cubic diamond and lonsdaleite based on the correlation between ab initio calculation and experimental results. We showed that the position of the single Raman vibration mode for cubic diamond corresponds to the first order scattering of F2g symmetry at 1332 cm−1. For lonsdaleite, the ab initio calculations predict three fundamental vibrational modes: 1207 cm−1 (E2g), 1307 cm−1 (A1g), and 1330 cm−1 (E1g). The calculated indirect bandgaps of 3C-diamond and lonsdaleite at room temperature are 5.7 eV and 5.2 eV, respectively. The elastic anisotropy calculations show that lonsdaleite has the greatest shear modulus, bulk modulus and young’s modulus compared to cubic diamond, which indicates a high degree of hardness of this hexagonal structure of diamond.

Fouling release coatings are known to be ecofriendly and to be a good alternative to the coatings containing biocides. To improve their efficiency and lifespan the incorporation of additives seems required. Amphiphilic system as PEG-silicone coatings have a lower impact on the environment. However, PEG oxidation in seawater impacts its lifespan. In this context, the development and incorporation of new hydrophilic additives offers great potentiel. The objective of this study is to design an amphiphilic fouling release coating containing poly(oxazoline) (POx) as additives. POx have similar physical properties as PEG and have already been used in biomedical applications. POx with a trimethoxysilane end-group has been synthesized to be crosslinked in a RTV silicone coating. The impact of its incorporation in a PDMS coating has been evaluated on surface properties and on coating organization. The results have been compared with a similar PEG-silicone coating. In addition, microbiologic assays have been carried out to evaluate the bacterial adhesion and the fouling properties of the coating. Two biomedicals bacteria and a marine bacterium were used to confirm the interest of POx. POx-silicone coating showed similar fouling efficiency against bacteria as PEG-silicone coating despite a bigger surface roughness and a lower compatibility with PDMS.

The alkylammonium halogenoferrate families are subjected to diverse studies according to their wide field application. However, these compounds show various transitions depending on the preparation process. In this paper, the [(C

Simple Summary Diatoms are microalgae known for their ecological importance. Among them, just a few species are able to produce a blue pigment. We describe Haslea silbo sp. nov., a cosmopolitan species of blue diatoms, found on both sides of the Atlantic Ocean. The description includes the use of both microscopy and next generation sequencing. It has been possible to observe its reproduction in the laboratory, and the blue pigment it produces has also been studied. Abstract Specimens of a new species of blue diatoms from the genus Haslea Simonsen were discovered in geographically distant sampling sites, first in the Canary Archipelago, then North Carolina, Gulf of Naples, the Croatian South Adriatic Sea, and Turkish coast of the Eastern Mediterranean Sea. An exhaustive characterization of these specimens, using a combined morphological and genomic approach led to the conclusion that they belong to a single new to science cosmopolitan species, Haslea silbo sp. nov. A preliminary characterization of its blue pigment shows similarities to marennine produced by Haslea ostrearia, as evidenced by UV–visible spectrophotometry and Raman spectrometry. Life cycle stages including auxosporulation were also observed, providing data on the cardinal points of this species. For the two most geographically distant populations (North Carolina and East Mediterranean), complete mitochondrial and plastid genomes were sequenced. The mitogenomes of both strains share a rare atp6 pseudogene, but the number, nature, and positions of the group II introns inside its cox1 gene differ between the two populations. There are also two pairs of genes fused in single ORFs. The plastid genomes are characterized by large regions of recombination with plasmid DNA, which are in both cases located between the ycf35 and psbA genes, but whose content differs between the strains. The two sequenced strains hosts three plasmids coding for putative serine recombinase protein whose sequences are compared, and four out of six of these plasmids were highly conserved.

Different polytypes of SiC are described and predicted in literature. Here, we report the first occurrence of an orthorhombic 6O-SiC polytype as rock-forming mineral in the nickel laterite mine of Tiebaghi (New Caledonia). This new class of SiC crystallizes in the space group Cmc21 with 12 atoms per unit cell [a = 3.0778(6) Å, b = 5.335(2) Å, c = 15.1219(6) Å, α = 90°, β = 90°, γ = 120°]. The density of 6O-SiC is about 3.22 g/cm3 and the calculated indirect bandgap at room temperature of 3.56 eV is identical to 6H-SiC. Our results suggest that 6O-SiC is the intermediate state in the wurtzite to rocksalt transformation of 6H-SiC.

International audience; Filamentous fungi are present everywhere in our environment and can grow on almost any substance in presence of moisture. Protecting the indoor environment against microbial growth remains a complex issue especially in sanitary applications or where protection against moulds is critical. Silicone samples containing 2% or 5% (w/w) of the cationic biocides polyhexamethylene guanidine dodecylbenzenesulfonate (PHMG-DBS), 1-octyl-3-me-thylimidazolium tetrafluoroborate (OMIM-BF 4) or 1-dodecyl-3-methylimidazolium tetrafluoroborate (DMIM-BF 4) were tested against a series of fungal species implicated in indoor fungal contamination. Our investigations were conducted according to the international standard ISO 16869 i.e. with a carbon-poor Nutrient-Salt-Agar (NSA) culture medium, and also with a carbon-rich Peptone-Dextrose-Agar (PDA) culture medium composed of pancreatic peptone, glucose and agar-agar as the spore suspension agar overlay. The experimental protocol using the PDA medium proved to be the most efficient procedure for discriminating, in a week only, the control analysis and those using modified silicones. Our results demonstrate that silicones containing 5% of polymeric biocide PHMG-DBS present higher antifungal activity on the filamentous fungi than longchain imidazolium ionic liquids-containing silicones. The possible mechanisms of antifungal action of cationic biocides are discussed. The efficacy of PHMG-DBS demonstrates that such modified-silicones can prevent microbial growth and silicone deterioration by microorganisms in areas with high humidity levels such as kitchens and bathrooms as well as hospitals and microbiology laboratories.

International audience; Different techniques have been combined to identify the structure and the chemical composition of siliceous breccia from a drill core of nickel laterites in New Caledonia (Tiebaghi mine). XRD analyses show quartz as a major phase. Micro-Raman spectroscopy confirmed the presence of reddish microcrystalline quartz as a major phase with inclusion of microparticles of iron oxides and oxyhydroxide. Lithoclasts present in breccia are composed of lizardite, chrysotile, forsterite, hedenbergite and saponite. The veins cutting through the breccia are filled with Ni-bearing talc. Furthermore, for the first time, we discovered the presence of diamond microcrystals accompanied by moissanite polytypes (SiC), chromite (FeCr2O4) and uranophane crystals (Ca(UO2)2(SiO3OH)2.5(H2O)) and lonsdaleite (2H-[C-C]) in the porosities of the breccia. The origin of SiC and diamond polytypes are attributed to ultrahigh-pressure crystallization in the lower mantle. The SiC and diamond polytypes are inherited from serpentinized peridotites having experienced interaction with a boninitic melt. Serpentinization, then weathering of the peridotites into saprolite, did not affect the resistant SiC polytypes, diamond and lonsdaleite. During karstification and brecciation, silica rich aqueous solutions partly digested the saprolite. Again, the SiC polymorph represent stable relicts from this dissolution process being deposited in breccia pores. Uranophane is a neoformed phase having crystallized from the silica rich aqueous solutions. Our study highlights the need of combining chemical and mineralogical analytical technologies to acquire the most comprehensive information on samples, as well as the value of Raman spectroscopy in characterizing structural properties of porous materials.

Plastic pollution has become one of the most visible environmental issue. Studying the aging and the fragmentation mechanism of polymers therefore raises environmental and health issues. Since it is particularly difficult to monitor all these processes in the real environment, laboratory studies are still necessary to obtain more accurate data and to identify the pathways leading to the outcome of plastic debris in the environment. In this paper we present a new method to prepare micrometer thick LDPE films with different thicknesses and controlled crystalline morphologies (i.e. spherulite size) using dip-coating process. LDPE films presenting different spherulite dimensions were submitted to an accelerated weathering test which indicates that spherulite size has only a weak influence on the rate of photo-oxidation. However, films presenting large spherulites morphologies seem to be more sensitive to surface erosion and crack initiation. We believe that the method developed in this paper can be used to study with more control and more rapidly (i.e. thin film and accelerated weathering) the influence of crystalline morphology on a wide range of semi-crystalline polymers in different ageing conditions and thus help to better understand the fragment production of plastics in the environment.

New protic ionic liquid N-butylguanidinium tetrafluoroborate (BG-BF4) has been synthesized by single-step method. The ionic liquid is thermally stable to at least 300 °C and has ionic conductivity value of 8⋅10−3 S/cm at room temperature increasing to 0.18 S/cm at 180 °C. To develop a new proton conducting membrane, the nano-fibrillar matrix of bacterial cellulose (BC) has been impregnated with BG-BF4. The composite BC/BG-BF4 membrane containing 80 wt% of ionic liquid was found to have tensile strength of 35 MPa and ionic conductivity of 4.5⋅10−4 S/cm at 180 °C. The high saturation of BC with protic ionic liquid to 95 wt% allowed obtain composite membrane with reduced tensile strength of 6 MPa but excellent ionic conductivity of 5.2⋅10−2 S/cm at 180 °C. The deposition of polyaniline (PANI, emeraldine base) into BC matrix by oxidative polymerization of aniline on the surface of cellulose nanofibrils was found to improve the ionic conductivity of BC/BG-BF4 system significantly, reaching the value of 4⋅10−3 S/cm at 180 °C for cellulose film containing 80 wt% of ionic liquid. According to results of dynamical mechanical analysis (DMA), both BC/BG-BF4 and BC/PANI/BG-BF4 composites keep excellent storage modulus values at 180 °C (1000 MPa and 835 MPa, respectively). Due to the excellent holding capacity of BC matrix to ionic liquid, as well as good thermal and mechanical properties of BC/BG-BF4 composite it can be promising material for the fabrication of proton conducting membranes for fuel cells operating at elevated temperatures in water free conditions.

International audience; In Normandy, the marine macroalgae become a large problem when the retreat of the tide leaves large quantities of stranded seaweed on coast. These stranded seaweeds can be toxic during their degradation in addition to creating odor problems. Consequently, their elimination has become a major problem and their recovery an emergency. In this work, we proposed to use the stranded seaweed in the building construction at a large scale. We investigated in particular the performance of insulated walls based on lightened earth incorporating reed and stranded Laminaria digitata seaweed at different substitution level. The compressive strength and the hygrothermal properties of the earth insulated walls specimens were carried out. Our results show that the incorporation of seaweed in lightened earth improves both its heat storage capacity and its level of insulation without compromising its compressive strength. The most efficient seaweed content for improving the thermal insulation of the material seems to be 20%. Indeed, the addition of 20% of Laminaria digitata decreased the thermal conductivity by 34% at 20 °C in comparison with standard cob. For this mixture, the specific heat capacity value is around 800 J.kg−1.K−1 at 20 °C, which are very high compared to that of the only earth-fiber specimen (400 J.kg−1.K−1). These increases in mechanical and hygrothermal performance of insulating cob material incorporating seaweed will lead to a reduction of the cob walls thickness and therefore to the development of sustainable energy efficient building materials with a low environmental impact.

International audience; The French gravel industry produces approximatively 6.5 million tons of gravel wash mud each year. This material offers very promising properties which require an in-depth characterization study before its use as a construction material, otherwise it is removed from value cycles by disposal in landfills. We examined the suitability of gravel wash mud and seashells, with fly ash as a binder, as an unfired earth construction material. Thermal and mechanical characterizations of the smart mixture composed of gravel wash mud, Crepidula fornicata shells and fly ash are performed. The new specimens exhibit high compressive strengths compared to usual earth construction materials, which appears as a good opportunity for a reduction in the thickness of walls. The use of fly ash and Crepidula shells in addition to gravel wash mud provides high silica and calcium contents, which both react with clay, leading to the formation of tobermorite and Al-tobermorite as a result of a pozzolanic reaction. Considering the reduction in porosity and improvements in strength, these new materials are good candidates to contribute significantly to the Sustainable Development Goals (SDGs) and reduce carbon emissions.

International audience; La2-xNdxCuO3.5 (x ≤ 0.5) compounds have been synthesized by a topotactic reduction reaction with calcium hydride at 280 °C for 48 h. Structural, thermal, vibrational and magnetic properties of La2-xNdxCuO3.5 (x ≤ 0.5) were studied by X-ray powder diffraction (XRD), by differential thermal analysis (DTA) and temperature dependent powder X ray diffraction (TDXD), by Raman spectroscopy and by electronic paramagnetic resonance. The oxidation of the compounds La2-xNdxCuO3.5 (x ≤ 0.5) at 400 °C for 24 h kinetically stabilizes the compounds La2-xNdxCuO4 (x ≤ 0.5) with an I4/mmm type structure. The phase relationship between T’ and T, ensured at high temperature, was followed and discussed by thermal and structural analysis.

A new polymeric biocide polyhexamethylene guanidine (PHMG) molybdate has been synthesized. The obtained cationic polymer has limited water solubility of 0.015 g/100 mL and is insoluble in paint solvents. The results of acute toxicity studies indicate moderate toxicity of PHMG molybdate, which has a median lethal dose at 48 h of 0.7 mg/L for Daphnia magna and at 96 h of 17 mg/L for Danio rerio (zebrafish) freshwater model organisms. Commercial ship paint was then modified by the addition of a low concentration of polymeric biocide 5% (w/w). The painted steel panels were kept in Dnipro River water for the evaluation of the dynamics of fouling biomass. After 129-d exposure, Bryozoa dominated in biofouling of tested substrates, forming 86% (649 g/m2 ) of the total biomass on control panel surfaces. However, considerably lower Bryozoa fouling biomass (15 g/m2 ) was detected for coatings containing PHMG molybdate. Dreissenidae mollusks were found to form 88% (2182 g/m2 ) of the fouling biomass on the control substrates after 228 d of exposure, whereas coatings containing PHMG molybdate showed a much lower biomass value of 23.6 g/m2 . The leaching rate of PHMG molybdate in water was found to be similar to rates for conventional booster biocides ranging from 5.7 μg/cm2 /d at the initial stage to 2.2 μg/cm2 /d at steady state. Environ Toxicol Chem 2017;36:2543-2551. © 2017 SETAC.

International audience; This paper reports on the synthesis and physical properties of conducting composites based on polyaniline and polystyrene. Polyaniline composite powders are synthesized by oxidative polymerization in an acidic medium. Thermal properties are characterized by thermo gravimetric analysis and differential scanning calorimetry. UV-Visible absorption spectroscopy is also used to study the optical properties of the deposited films. The optical gap decreases from 4.6 eV to 2.7 eV with increasing polyaniline content from 0.5 to 5 wt. % confirming the improvement of the semi-conductive properties. Due to the absorption properties in near infrared of the thin composite layers they can be promising materials for optoelectronic and photovoltaic applications.

The present study focused on the physical and electrochemical properties of stannic sulfide SnS2 synthesized by a template-free chemical route using thiourea as a precursor. SnS2 powder was characterized by X-ray diffraction (XRD), diffuse reflectance and Raman. The XRD pattern confirmed the formation of the hexagonal phaseSnS2 (SG: P-3m1) with the lattice parameters a = 3.639 A, c = 5.868 A and a mean crystallite size of ~ 60 nm. The optical measurements gave a direct transition of 2.26 eV, further transition indirectly allowed was observed at 1.63 eV. The Mott-Schottky plot recorded in Na2SO4 (0.1 M) electrolyte exhibits a linear behavior, characteristic of n-type conductivity and confirmed by chronoamperometry. The flat band potential (−0.63 VSCE) is close to the photocurrent onset potential (Eon= −0.64 VSCE) and a donor density of 3.54 × 1016 cm−3 was determined. The electrochemical impedance spectroscopy measured in the range (10−2 − 5 × 104 Hz) showed two semicircles assigned to a faradic charge transfer (Rct = 2.46 kΩ cm2) and grain boundaries contribution (Rgb= 13.69 kΩ cm2). The conduction band, located at −4.02 eV below vacuum, is made up of Sn4+: 5p while the valence band (−6.28 eV) derives mainly from S2−: 3p. As an application, Rhodamine B was successfully oxidized by photocatalysis on SnS2, 93.67% of the initial concentration (10 mg L−1) disappeared after 3 h of exposure to solar light (90 mW cm−2).

The choice of efficient antimicrobial additives for polyamide resins is very difficult because of their high processing temperatures of up to 300 &deg, C. In this study, a new, thermally stable polymeric biocide, polyhexamethylene guanidine 2-naphtalenesulfonate (PHMG-NS), was synthesised. According to thermogravimetric analysis, PHMG-NS has a thermal degradation point of 357 &deg, C, confirming its potential use in joint melt processing with polyamide resins. Polyamide 11 (PA-11) films containing 5, 7 and 10 wt% of PHMG-NS were prepared by compression molding and subsequently characterised by FTIR spectroscopy. The surface properties were evaluated both by contact angle, and contactless induction. The incorporation of 10 wt% of PHMG-NS into PA-11 films was found to increase the positive surface charge density by almost two orders of magnitude. PA-11/PHMG-NS composites were found to have a thermal decomposition point at about 400 &deg, C. Mechanical testing showed no change of the tensile strength of polyamide films containing PHMG-NS up to 7 wt%. Antibiofilm activity against the opportunistic bacteria Staphylococcus aureus and Escherichia coli was demonstrated for films containing 7 or 10 wt% of PHMG-NS, through a local biocide effect possibly based on an influence on the bacterial eDNA. The biocide hardly leached from the PA-11 matrix into water, at a rate of less than 1% from its total content for 21 days.

The fully open character of the Raman Open Database makes this novel database freely and completely usable by anybody worldwide: academics, those working in industry and the general public., Detailed crystallographic information provided by X-ray diffraction (XRD) is complementary to molecular information provided by Raman spectroscopy. Accordingly, the combined use of these techniques allows the identification of an unknown compound without ambiguity. However, a full combination of Raman and XRD results requires an appropriate and reliable reference database with complete information. This is already available for XRD. The main objective of this paper is to introduce and describe the recently developed Raman Open Database (ROD, http://solsa.crystallography.net/rod). It comprises a collection of high-quality uncorrected Raman spectra. The novelty of this database is its interconnectedness with other open databases like the Crystallography Open Database (http://www.crystallography.net/cod and Theoretical Crystallography Open Database (http://www.crystallography.net/tcod/). The syntax adopted to format entries in the ROD is based on the worldwide recognized and used CIF format, which offers a simple way for data exchange, writing and description. ROD also uses JCAMP-DX files as an alternative format for submitted spectra. JCAMP-DX files are compatible to varying degrees with most commercial Raman software and can be read and edited using standard text editors.

New hydrophobic protic ionic liquid, 2-butylaminoimidazolinium bis(trifluoromethylsulfonyl)imide (BAIM-TFSI), has been synthesized. The ionic liquid showed good thermal stability to at least 350 °C. The conductivity of BAIM-TFSI determined by electrochemical impedance method was found to be 5.6 × 10−2 S/cm at 140 °C. Homogeneous composite films based on commercial polyimide (PI) Matrimid and BAIM-TFSI containing 30–60 wt% of ionic liquid were prepared by casting from methylene chloride solutions. Thermogravimetric analysis data indicated an excellent thermal stability of PI/BAIM-TFSI composites and thermal degradation points in the temperature range 377 °C–397 °C. The addition of ionic liquid up to 50 wt% in PI films does not lead to any significant deterioration of the tensile strength of the polymer. The dynamic mechanical analysis results indicated both an increase of storage modulus E′ of PI/BAIM-TFSI composites at room temperature and a significant E′ decrease with temperature compared with the neat polymer. The cross-linking of the PI with polyetheramine Jeffamine D-400 allowed to prepare PI/Jeffamine/BAIM-TFSI (50%) membrane with E′ value of 300 MPa at 130 °C. The ionic conductivity of this cross-linked composite membrane reached the level of 10−2 S/cm at 130 °C, suggesting, therefore, its potential use in medium-temperature fuel cells operating in water-free conditions.

International audience; A new telechelic liquid natural rubber is used to elaborate thin coating (

International audience; Borosilicate glasses are considered for the long-term confinement of high-level nuclear wastes. External irradiations with 1 MeV He+ ions and 7 MeV Au5+ ions were performed to simulate effects produced by alpha particles and by recoil nuclei in the simulated SON68 nuclear waste glass. To better understand the structural modifications, irradiations were also carried out on a 6-oxides borosilicate glass, a simplified version of the SON68 glass (ISG glass). The mechanical and macroscopic properties of the glasses were studied as function of the deposited electronic and nuclear energies. Alpha particles and gold ions induced a volume change up to −0.7% and −2.7%, respectively, depending on the glass composition. Nano-indentations tests were used to determine the mechanical properties of the irradiated glasses. A decrease of about −22% to −38% of the hardness and a decrease of the reduced Young's modulus by −8% were measured after irradiations. The evolution of the glass structure was studied by Raman spectroscopy, and also 11B and 27Al Nuclear Magnetic Resonance (MAS-NMR) on a 20 MeV Kr irradiated ISG glass powder. A decrease of the silica network connectivity after irradiation with alpha particles and gold ions is deduced from the structural changes observations. NMR spectra revealed a partial conversion of BO4 to BO3 units but also a formation of AlO5 and AlO6 species after irradiation with Kr ions. The relationships between the mechanical and structural changes are also discussed

Water immiscible ionic liquid 1-dodecyl-3-methylimidazolium tetrafluoroborate (DMIM-BF 4 ) and its inclusion complex with β-cyclodextrin (β-CD) in molar ratio 1:1 have been synthesized. The formation of DMIM-BF 4 /β-CD complex was confirmed by FT-IR analysis, 1 H NMR analysis, and differential scanning calorimetry data. Our results indicate that the aliphatic tail of DMIM-BF 4 is included into β-CD inner cavity whereas imidazolium ring is located outside the torus. Moreover, the weak interaction between polar components of ionic liquid and hydrophilic outer surface of β-CD has also been detected. The standard agar disk diffusion method was performed to evaluate antimicrobial efficiency of the obtained compounds against Staphylococcus aureus (ATCC-25923), Escherichia coli (ATCC-25922) and Pseudomonas aeruginosa (ATCC-27853), Candida albicans (M 885 ATCC 10231) and its clinical isolate test-cultures. It has been found that both DMIM-BF 4 and DMIM-BF 4 /β-CD complex possess high antimicrobial activity as revealed by similar zone inhibition values against all tested microorganisms. The acute toxicity studies on Danio rerio (zebrafish) model organism showed that the pure ionic liquid DMIM-BF 4 is slightly toxic compound having LD 50 value of 7 mg/L, whereas DMIM-BF 4 /β-CD complex has considerably reduced toxicity (LD 50 = 100 mg/L) and therefore have potentially wider application areas.

International audience

Controlling adsorption of proteins onto medical devices is a key issue for implant-related infections. As self-assembled monolayers (SAMs) on titanium oxide represent a good model to study the surface-protein interactions, TiO 2 surface properties were modified by grafting bisphosphonate molecules terminated with hydrophilic poly(ethylene glycol) groups and hydrophobic perfluoropolyether ones, respectively. Characterisation of the surface chemistry and surface topography of the modified surfaces was performed using XPS and atomic force microscopy (AFM). Quartz-crystal microbalance with dissipation (QCM-D) was used to determine the mass of adsorbed proteins as well as its kinetics. Poly(ethylene glycol)-terminated SAMs were the most effective surfaces to limit the adsorption of both BSA and fibrinogen in comparison to perfluorinated-terminated SAMs and non-modified TiO 2 surfaces, as expected. The adsorption was not reversible in the case of BSA, while a partial reversibility was observed with Fg, most probably due to multilayers of proteins. The grafted surfaces adsorbed about the same quantity of proteins in terms of molecules per surface area, most probably in monolayer or island-like groups of adsorbed proteins. The adsorption on pristine TiO 2 reveals a more important, non-specific adsorption of proteins.

The present experimental measurements reveal that similar to external fields such as electric, magnetic, or flow fields, the vicinity of a solid surface can preclude the liquid molecules from relaxing to equilibrium, generating located non-uniform temperatures. The non-uniform temperature zone extends up to several millimeters within the liquid with a lower temperature near the solid wall (reaching ΔT = −0.15 °C ± 0.02 °C in the case of liquid water) counterbalanced at larger distances by a temperature rise. These effects highlighted by two independent methods (thermistor measurement and infra-red emissivity) are particularly pronounced for highly wetting surfaces. The scale over which non-uniform temperatures are extended indicates that the effect is assisted by intermolecular interactions, in agreement with recent developments showing that liquids possess finite shear elasticity and theoretical approaches integrating long range correlations.

International audience; In this work, we report on magnetic nanoparticles of CoxFe3-XO4 (x 0) gives spinel structure of space group Fd-3m for all samples. Magnetization curves, recorded by a Vibrating Sample Magnetometer (VSM), are the sign of two exchange-coupled magnetic phases (x > 0). This was in disagreement with XRD and SAED analyses which showed only one structural phase. Large (similar to 250 nm and less) rectangular and small spheroidal nanoparticles have been found by Transmission Electron Microscopy (TEM). The increase of cobalt content favors the formation of monodisperse nanoparticles. Following a subsequent heat treatment, a fraction of the as prepared samples (depending on x) has been transformed into hematite phase with a disappearance of the exchange-coupling behavior. In situ Micro-Raman analyses were necessary to investigate on the growing of the nanoparticles and the ferrite-hematite transformation. We have also deduced, that the synthesized phase with the cobalt ferrite one (till x < 1) was the magnetite Fe3O4. Then, we have pointed out the effect of performing local spectroscopy and the effect of having mixed ferrites on the structural and the physical properties. (C) 2016 Elsevier B.V. All rights reserved.

International audience; We investigated the carbon steel corrosion in carbon dioxide clay-rich environment to understand its behavior under geological conditions. The results show the formation of magnetite as the main corrosion product in the first step of the corrosion process, followed by the formation of different corrosion products with complex mixtures of iron-oxide, hydroxycarbonate, hydroxychloride and sulfide phases. These results strongly contrast with similar experiments conducted under H-2 atmosphere where the major corrosion products consisted of iron sulfides. It appears then important to consider all the geochemical parameters including gas composition to better study corrosion of steel buried in geological formations. (C) 2014 Elsevier Ltd. All rights reserved.

To elaborate a new antimicrobial bacterial cellulose (BC) based material, the porous structure of BC has been combined with polymeric biocide polyhexamethylene guanidine hydrochloride (PHMG-Cl). A sufficient saturation of the BC matrix with PHMG-Cl and the formation of hydrogen bonds between chloride ions of the polymeric biocide and the hydroxyl groups of BC was confirmed by FT-IR analysis. The formation of an interconnected network of fiber bundles within the cellulose-based composite after the introduction of PHMG-Cl was revealed by Atomic Force Microscopy (AFM). The modified PHMG-Cl biocide bacterial cellulose film specimens showed excellent efficacy against multidrug resistant strains Staphylococcus aureus and Klebsiella pneumonia IMBG233, the phytopatogenic Xanthomonas campestris pv. campestris IMBG299 and Pseudomonas syringae pv. tomato DC3000, as well as yeast. Moreover, the introduction of PHMG-Cl also prevented a biofilm formation by a model association of pro- and eukaryotic microorganisms and stopped de novo cellulose synthesis in the existed biofilm. The biocide release rate from BC matrix was shown to depend on the moisture content of the composite films. PHMG-Cl-embedded cellulose is therefore a new formulation of biocide which could be further used for wounds healing.

© 2014 by Pleiades Publishing, Ltd. In this work we assessed the performance of the density functional theory (DFT) approach through a comparison study with the experimental Raman spectrum obtained for [4-[( E)-phenylazo]phenyl]ethanol (ABOH) in the wave number range 900-1800 cm-1. The assignment of the ten most active vibrational modes is achieved using the hybrid B3LYP method with the 6-311++G(2d,2p) basis set. Two molecules of reference [N-ethyl-4-[( E)-(4-nitrophenyl)azo]anilino]ethanol (Disperse Red 1, DR1) and 4-[( E)-(4-nitrophenyl) azo]aniline (Disperse Orange 3, DO3) are also investigated in order to consider this method in the calculation of the Raman intensities. The experimental Raman spectrum of DR1 is compared with those of the three stable configurations obtained at the B3LYP/6-311++G(2 d,2p) level.

In diatoms, the main photosynthetic pigments are chlorophylls a and c, fucoxanthin, diadinoxanthin and diatoxanthin. The marine pennate diatom Haslea ostrearia has long been known for producing, in addition to these generic pigments, a water-soluble blue pigment, marennine. This pigment, responsible for the greening of oysters in western France, presents different biological activities: allelopathic, antioxidant, antibacterial, antiviral, and growth-inhibiting. A method to extract and purify marennine has been developed, but its chemical structure could hitherto not be resolved. For decades, H. ostrearia was the only organism known to produce marennine, and can be found worldwide. Our knowledge about H. ostrearia-like diatom biodiversity has recently been extended with the discovery of several new species of blue diatoms, the recently described H. karadagensis, H. silbo sp. inedit. and H. provincialis sp. inedit. These blue diatoms produce different marennine-like pigments, which belong to the same chemical family and present similar biological activities. Aside from being a potential source of natural blue pigments, H. ostrearia-like diatoms thus present a commercial potential for aquaculture, cosmetics, food and health industries.

In this paper, we studied the effect of sulfide ions on the corrosion behavior of carbon steel to simulate the geological disposal of high-level radioactive waste. In geological storage conditions, sulfidogenic environment was sustained by sulfate-reducing bacteria. Corrosion tests were conducted in systems in a controlled atmosphere of 5% H-2/N-2. Batch experiments were conducted at 30A degrees C for 1 month with steel coupons immersed in Na2S solutions. The structural characterization of the corrosion products was investigated by scanning electron microscope/energy dispersive x-ray spectroscopy, confocal micro-Raman spectrometry, and x-ray diffraction. In the absence of sulfide ion, a magnetite (Fe3O4) corrosion product layer was formed on steel surface while in the presence of sulfide ions we observed the formation of a poorly crystallized irons sulfide at low-sulfide concentration (1 mg/L) and a solid adherent pyrrhotite layer at higher sulfide concentration (5-15 mg/L). The strong drop in steel corrosion rate with sulfide concentration was revealed and related to the formation of well-crystallized pyrrhotite.

International audience; The mackinawite mineral was prepared as a carbon steel corrosion product in sulfidogenic waters at 90 degrees C after 2 months. The tetragonal crystal structure of the material was confirmed by Rietveld refinement of X-ray diffraction (XRD) data, and vibrational modes were analysed by micro-Raman spectroscopy. Despite a large number of studies on the formation and the stability of tetragonal mackinawite, the interpretation of the Raman spectra remains uncertain. In the present study, we report on the first calculation of the Raman-active vibrational modes of mackinawite using Density Functional Perturbation Theory and direct methods with BLYP + dispersion correction. Based on the comparison between calculated and experimental results, the four fundamental vibrational modes were assigned as 228 cm(-1) (B-1g), 246 cm(-1) (E-g), 373 cm(-1) (A(1g)) and 402 cm(-1) (E-g).

We have tested silicones containing 2% or 5% of the cationic biocides polyhexamethylene guanidine dodecylbenzenesulfonate (PHMG-DBS), 1-octyl-3-methylimidazolium tetrafluoroborate (OMIM-BF4) or 1-dodecyl-3-methylimidazolium tetrafluoroborate (DMIM-BF4) against the major relevant bacterial and yeast species in health care-associated infections (HCAI). Study conducted according to the international standard ISO 22196 revealed that silicones containing 2% or 5% DMIM-BF4 or 5% PHMG-DBS presented the highest antimicrobial activity, leading to a logarithmic growth reduction of 3.03 to 6.46 and 3.65 to 4.85 depending on the bacterial or fungal species. Heat-pretreated silicones containing 2% DMIM-BF4 kept a high activity, with at least a 3-log reduction in bacterial growth, except against P. aeruginosa where there was only a 1.1-log reduction. After 33days, the release ratio of cationic biocide from silicone films containing 5% of DMIM-BF4 was found to be 5.6% in pure water and 1.9% in physiological saline solution, respectively. No leaching of PHMG-DBS polymeric biocide was detected under the same conditions. These results demonstrate unambiguously that silicones containing 2% DMIM-BF4 or 5% PHMG-DBS present high antimicrobial activity, as well as high leaching resistance and therefore may be good candidates for the development of safer medical devices.

Antimicrobial polyamide 11 (PA-11) films containing low-cost, thermally stable and water resistant polymeric biocide polyhexamethylene guanidine dodecylbenzenesulfonate (PHMG-DBS) have been obtained by compression moulding. The structure of the modified PA-11 films containing from 3 to 10 wt% of PHMG-DBS was characterized using Raman and FTIR spectroscopy and atomic force microscopy (AFM). The surface properties were evaluated both by contact angle and contactless inductive method. The introduction of PHMG-DBS into PA-11 films was found to increase positive surface charge density to 5.5·10−11 C/cm2 for 10 wt% of PHMG-DBS. Antibacterial activity of PA-11/PHMG-DBS films against both Gram-positive (Escherichia coli) and Gram-negative (Bacillus subtilis) bacteria was demonstrated for films containing from 5 to 7 wt% of polymeric biocide. According to thermal investigations data, PA-11/PHMG-DBS composite has excellent thermal stability to at least 390 °C both in air and in argon atmosphere which indicates on its availability for the melt processing by common methods. It has also been found that polymeric biocide is highly resistant to leaching from PA-11 film.

International audience

A new species of raphid pennate diatom producing a blue pigment, Haslea karadagensis Davidovich, Gastineau & Mouget, sp. nov., was recently isolated from the Crimean coast of the Black Sea (Ukraine). This organism is very similar to the well-known Haslea ostrearia, the first described ‘blue’ diatom, which produces marennine, the pigment involved in the greening of oysters. The Ukrainian diatom, H. karadagensis, differs slightly from H. ostrearia in the structure of its frustule, and the two organisms are unable to interbreed. Two molecular markers, rbcL and the ITS1–5.8S–ITS2 sequences, showed 2% and >50% differences, respectively, between the two species. UV-visible spectrophotometry and in vivo confocal micro-Raman spectroscopy were used to compare the pigment of H. karadagensis with marennine. Both pigments showed absorption bands in the UV and red regions, but the positions of the maxima differ between the pigments. Significant differences were observed by micro-Raman spectroscopy in the 1000–1700 cm−...

Calcium carbonate (CaCO3)/iron oxide composites were synthesized through a simple one-step impregnation procedure by mixing iron oxide nanoparticles (γ-Fe2O3 and Fe3O4) of about 6 nm in size and CaCO3 microparticles (Φ = 2 µm–8 µm, vaterite phase). The morphology and structural properties of CaCO3, iron oxide nanoparticles and CaCO3/iron oxide composites were characterized as a function of low iron content (0 %w to 3.2 %w) by scanning electron microscopy and transmission electron microscopy, X-ray diffraction and 57Fe Mossbauer spectrometry. The phase transformations induced by thermal treatment and laser irradiation were investigated in situ by X-ray thermodiffraction (XRTD) and Raman spectroscopy. We have shown that the phase transformations observed by XRTD are also observed under laser irradiation as a consequence of the absorption of the laser irradiation by iron oxide nanoparticles. Copyright © 2012 John Wiley & Sons, Ltd.

Water-resistant polymeric biocide poly(hexamethylene guanidine) dodecylbenzenesulfonate (PHMG-DBS) was synthesized by anion metathesis between poly(hexamethylene guanidine) hydrochloride and sodium dodecylbenzenesulfonate and subsequently characterized using elemental analysis, Raman spectroscopy and thermogravimetric analysis. It is found that PHMG-DBS is thermally stable to at least 350 °C, which makes it suitable for melt blending with polyamide (PA) resins. An antifungal PA-12 composition was prepared by compression moulding of PA-12 and PHMG-DBS powder mixture at 240 °C. The characteristics of the prepared films were investigated: surface roughness and hydrophobicity using atomic force microscopy and contact angle measurements, respectively. No significant change in the material characteristics is observed compared to pure PA-12 films. PA-12 films containing 2 wt% of the PHMG-DBS biocide are found to be highly resistant against Trychophyton mentagrophytes fungus. Copyright © 2012 Society of Chemical Industry