Abstract: The present work reports on the application and the evaluation of a multitude of crosslinking approaches including high-energy irradiation, redox-initiating systems and conventional carbodiimide-coupling chemistry for frozen and/or freeze-dried porous gelatin scaffolds. The latter is particularly relevant for a plethora of biomedical applications such as tissue engineering supports, wound dressings, adhesive and absorbent pads for surgery, etc. Moreover, the results obtained for gelatin can be considered a proof-of-concept to be extrapolated to other polymer systems containing double bonds and/or amines and carboxylic acids to also realize scaffold crosslinking in dry or frozen state. The results showed that high-energy irradiation at -5 A degrees C enabled sufficient segmental mobility to induce chemical crosslinking after performing a cryogenic treatment of methacrylamide-modified gelatin scaffolds. Alternatively, although several redox-initiating systems were unable to chemically crosslink functionalized gelatin, the combination of ammonium persulphate and TEMED resulted in the formation of scaffolds with a reasonable gel fraction. Interestingly, carbodiimide-coupling was found suitable to crosslink freeze-dried gelatin matrices.

Abstract: The use of temperature-time series measured in streambed sediments as input to coupled water flow and heat transport models has become standard when quantifying vertical groundwater-surface water exchange fluxes. We develop a novel methodology, called LPML, to estimate the parameters for 1-D water flow and heat transport by combining a local polynomial (LP) signal processing technique with a maximum likelihood (ML) estimator. The LP method is used to estimate the frequency response functions (FRFs) and their uncertainties between the streambed top and several locations within the streambed from measured temperature-time series data. Additionally, we obtain the analytical expression of the FRFs assuming a pure sinusoidal input. The estimated and analytical FRFs are used in an ML estimator to deduce vertical groundwater-surface water exchange flux and its uncertainty as well as information regarding model quality. The LPML method is tested and verified with the heat transport models STRIVE and VFLUX. We demonstrate that the LPML method can correctly reproduce a priori known fluxes and thermal conductivities and also show that the LPML method can estimate averaged and time-variable fluxes from periodic and nonperiodic temperature records. The LPML method allows for a fast computation of exchange fluxes as well as model and parameter uncertainties from many temperature sensors. Moreover, it can utilize a broad frequency spectrum beyond the diel signal commonly used for flux calculations.

Abstract: Human urine contains a high concentration of nitrogen and is therefore an interesting source for nutrient recovery. Ureolysis is a key requirement in many processes aiming at nitrogen recovery from urine. Although ureolytic activity is widespread in terrestrial and aquatic environments, very little is known about the urease activity and regulation in specific bacteria other than human pathogens. Given the relatively high salt concentration of urine, marine bacteria would be particularly well suited for biotechnological applications involving nitrogen recovery from urine, and therefore, in this study, we investigated ureolytic activity and its regulation in marine vibrios. Thirteen out of 14 strains showed ureolytic activity. The urease activity was induced by urea, since complete and very rapid hydrolysis, up to 4 g L-1 of urea, was observed in synthetic human urine when the bacteria were pretreated with 10 g L-1 urea, whereas slow hydrolysis occurred when they were pretreated with 1 g L-1 urea (14-35% hydrolysis after 2 days). There was no correlation between biofilm formation and "motility on one hand, and ureolysis on the other hand, and biofilm and motility inhibitors did not affect ureolysis. Together, our data demonstrate for the first time the potential of marine vibrios as fast urea hydrolyzers for biotechnological applications aiming at nutrient recovery from human urine.

Abstract: Using the mass-spectrometric method we study the charge, energy and spatial characteristics of ions in multicomponent plasma, generated under the action of Nd : YAG laser radiation on the surface of solid targets. We focus on the effect of the entry form of light gas atoms on the parameters of ions in such laser-produced plasmas. We found that the presence of light gas atoms considerably affects the parameters (e.g. the intensity and the charge multiplicity) of the heavier ions.

Abstract: Grains of K-feldspar are commonly seen as heterogeneous mixtures of mineral species and varieties with random microstructures. Most consider that observable features arise from incomplete re-equilibrations owing to slow kinetic and localized effects of aqueous fluids (catalyst), with geological environment and chemical impurities playing only a secondary role. Here, an alternative approach is explored by studying well-preserved regularities in the twin patterns of K-feldspars formed in the subsolidus stage from a historical perspective. Selected samples from granitic pegmatites were studied by polarized light optical microscopy (PLOM), electron-probe micro-analysis (EPMA), scanning (SEM) and transmission electron microscopy (TEM), cathodoluminescence imaging (CL), micro-Raman spectroscopy (MRS) and 31P nuclear magnetic resonance (NMR). We have found that the essential feature of this crystalline medium is the astounding capability to recrystallize in self-organized twin patterns. The mechanism involves coupling between short-range atomic motion, and long-range displacive correlations propagated as ideal and non-ideal Albite and Pericline orientations. We suggest a general evolutionary process to explain the development of macroscopic twin patterns in microcline, based on three twin generations as microtwins, macrotwins and cryptotwins. Evolutionary variants also were identified; they depend on both internal crystallochemical features and an external geological stimulus. We suggest a continuous monoclinictriclinic transformation for impure K-feldspar, whereas a discontinuous inversion occurs where the starting composition is close to the ideal chemical formula. Twin patterns can evolve by twin coarsening to single-orientation microcline if the system releases energy, or by twin fragmentation to finely twinned microcline if the system stores energy. Hence, K-feldspar is seen here as a very sensitive medium in which precious geological information is recorded in the form of twin patterns, and thus useful for general geological challenges.

Abstract: Now they are 10! The title compound displays a new type of crystal structure and is labeled clathrate X according to the general classification of clathrate structures. In contrast to typical clathrates, this compound has three-coordinate atoms within the framework and combines distorted 24-vertex polyhedra (see picture, green) centered around tellurium guest atoms with very irregular 10-vertex polyhedra around sulfur atoms (yellow).

Abstract: Magnetoreflectivity measurements of the 1s and 2s exciton energies in a CdTe/Cd1-xMnxTe superlattice have been made in magnetic fields up to 45 T, showing the resonant polaron coupling of electrons to LO phonons. Strong reflectivity features are seen for both the 1s and 2s excitons, which show a strong field-dependent spin splitting due to the dilute magnetic barriers. At B-z=0, the 2s exciton feature is observed lying 18 meV above the Is state, and is shifted upward in energy by the magnetic fields. No resonant behavior occurs when the 2s state passes through the LO-phonon energy of 21 meV, but at higher fields of around 20 T, the resonances for both spin states (sigma(+/-)) of the 2s exciton broaden and show a strong anticrossing behavior. These experiments are shown to be in excellent agreement with a theoretical treatment which includes the resonant polaron coupling of the electrons alone. Both experiment and theory demonstrate an extremely strong resonant splitting of the 2s exciton states of approximately 11 meV, which is over 50% of the LO-phonon energy. The dominance of single-particle polaron coupling is attributed to the relative sizes of the polaron (35 Angstrom A) and the exciton (50 Angstrom A) radius.

Abstract: A diazonium based-arylation reaction was efficiently used for the covalent addition of 4-amino-N,N,N-trimethylbenzene ammonium to stable dispersions of few layer graphene (FLG) yielding an innovative FLG platform with positive charges to immobilize inorganic polyanions.

Abstract: Here, we present routes to increase CO2 conversion into CO using an atmospheric pressure dielectric-barrier discharge. The change in conversion as a function of simple plasma parameters, such as power, flow rate, but also frequency, on-and-off power pulse, thickness and the chemical nature of the dielectric, wall and gas temperature, are described. By means of an in-depth electrical characterization of the discharge (effective plasma voltage, dielectric voltage, plasma current, number and lifetime of the microdischarges), combined with infrared analysis of the walls of the reactor, optical emission spectroscopy for the gas temperature, and mass spectrometry for the CO2 conversion, we propose a global interpretation of the effect of all the experimental parameters on the conversion and efficiency of the reaction.