Anodization behaviour and basic property mapping in the aluminium-erbium system

A co-evaporation technique was used for depositing an Al-Er thin film combinatorial library on borosilicate glass substrates with Er concentrations between 3 and 21 at.% and a total compositional resolution of 0.25 at.% mm⁻¹. Scanning droplet cell microscopy was employed for compositional mapping of several fundamental properties of mixed oxides grown on Al-Er thin film alloys. Microstructural and crystallographic particularities of Al-Er alloys were identified along the library, and a relevant compositional threshold at around Al-5 at.% Er was identified. Further, small surface grains in the nanometre range were found at Al grain boundaries, and an initial amorphization and/or hexagonal phase nucleation was identified for Er amounts around 5 at.%. Electrochemical studies revealed the importance of this compositional threshold, as distinct maximizations of oxide formation factors and oxide electrical permittivities were observed.

     

Thermal Gaussian molecular dynamics for quantum dynamics simulations of many-body systems: application to liquid para-hydrogen

A new method, here called thermal Gaussian molecular dynamics (TGMD), for simulating the dynamics of quantum many-body systems has recently been introduced [I. Georgescu and V. A. Mandelshtam, Phys. Rev. B 82, 094305 (2010)]. As in the centroid molecular dynamics (CMD), in TGMD the N-body quantum system is mapped to an N-body classical system. The associated both effective Hamiltonian and effective force are computed within the variational Gaussian wave-packet approximation. The TGMD is exact for the high-temperature limit, accurate for short times, and preserves the quantum canonical distribution. For a harmonic potential and any form of operator A?, it provides exact time correlation functions C(AB)(t) at least for the case of B, a linear combination of the position, x, and momentum, p, operators. While conceptually similar to CMD and other quantum molecular dynamics approaches, the great advantage of TGMD is its computational efficiency. We introduce the many-body implementation and demonstrate it on the benchmark problem of calculating the velocity time auto-correlation function for liquid para-hydrogen, using a system of up to N = 2592 particles.     

Cyclophanes or Cyclodextrins: What is the Best Host for Aromatic Volatile Organic Compounds?

The first results of the complexing ability of cyclobis-(paraquat-p-phenylene) as supramolecular host with different aromatic volatile organic compounds are presented. The formation constants of cyclobis(paraquat-p-phenylene) with toluene and halogenobenzenes were determined in aqueous solution by static headspace associated with gas chromatography and compared with the ones obtained by cyclodextrins. The data indicated the formation of 1:1 inclusion compounds in both cases. The results underlined a greater complexation ability for cyclobis(paraquat-p-phenylene) which was confirmed by a theoretical study.     

Facilitated transport of 5-aminosalicylic acid through bulk liquid membrane

This paper describes the experimental results obtained at the transport of 5-aminosalicylic acid (5ASA) through agitated bulk liquid membrane, using Aliquat 336, as carrier, dissolved in a chloroform membrane. The influence of 5-aminosalicylic acid concentration in the feed source, HCl concentration in the stripping phase and carrier (Aliquat 336) concentration in the membrane were investigated. The optimal pH condition of feed source was established based on the speciation diagram of 5-aminosalicylic acid. The assessment of the transport process was performed by determining the kinetic parameters—mass transfer coefficient and entrance and exist flow in and out of the chloroform membrane.     

Thermal decomposition,kinetic study and evolved gas analysis of 1,3,5-triazine-2,4,6-triamine

The thermo-physical properties for four rock types (granite, granodiorite, gabbro, and garnet amphibolite) from room temperature to 1,173 K were investigated. Thermal diffusivity and specific heat capacity were measured using the laser-flash technique and heat flux differential scanning calorimetry, respectively. Combined with the density data, rock thermal conductivities were calculated. Rock thermal diffusivity and conductivity decrease as the temperature increases and approach a constant value at high temperatures. At room temperature, the measured thermal conductivity is consistently near or lower than the calculated conductivity using the mineral series model, which suggests that real thermal conduction is more complicated than is depicted in the model. Therefore, in situ measurement remains the best method for accurately obtaining thermal conductivity for rocks.     

Influence of Plasma Treatments on the Hemocompatibility of PET and PET + TiO2 Films

A dielectric barrier discharge (DBD) in helium was used to ameliorate the interface between the blood and the surface of polymeric implants: polyethylene terephthalate (PET) and PET with titanium oxide (PET + TiO₂). A higher crystallinity degree was found for the DBD treated samples. The wettability of polymers was improved after the treatment. The chemical composition, analyzed by infrared spectroscopy was preserved during the DBD treatment. The surface modifications have been correlated with polymers hemocompatibility. Concerning the polymer surface–blood interaction, the treatment induced a decrease of the interfacial tension between the blood components and the treated surfaces. The in vitro tests of hemocompatibility showed no perturbation in the blood composition when the polymer samples are present in the blood volume. An interesting result is related to the whole blood clotting time that shows a dramatic increase on the treated surfaces. Moreover, the coagulation kinetics on the treated surfaces is modified.     

W*-rigidity for the von Neumann algebras of products of hyperbolic groups

We show that if \({\Gamma = \Gamma_1\times\dotsb\times \Gamma_n}\) is a product of \({{\rm n} \geq 2}\) non-elementary ICC hyperbolic groups then any discrete group \({\Lambda}\) which is \({W^*}\)-equivalent to \({\Gamma}\) decomposes as a direct product of n ICC groups and does not decompose as a direct product of k ICC groups when \({{\rm n} \not= {\rm k}}\). This gives a group-level strengthening of Ozawa and Popa’s unique prime decomposition theorem by removing all assumptions on the group \({\Lambda}\). This result in combination with Margulis’ normal subgroup theorem allows us to give examples of lattices in the same Lie group which do not generate stably equivalent II₁ factors.     

Anodic oxide formation on aluminium-terbium alloys

Aluminium terbium alloys were prepared by simultaneous thermal evaporation resulting in a thin film library covering a 5 to 25 at.% Tb compositional spread. Synchrotron x-ray diffraction (XRD) proves all of the alloys to be amorphous. Scanning electron microscopy (SEM) measurements reveal the structural changes upon increase in Tb content with the formation of small, Tb-rich segregations right before a drastic change in morphology around 25 at.% Tb. Anodic oxides were formed systematically in cyclic voltammograms using scanning droplet cell microscopy. Coulometric analysis revealed a linear thickness over formation potential behaviour with film formation factors ranging from 1.2 nm V^?1 (5 at.% Tb) to 1.6 nm V^?1 (25 % Tb). Electrochemical impedance spectroscopy was performed for each incremental oxidation step resulting in a linear relation between inverse capacity and formation potential with dielectric constants ranging from 8 (5 at.% Tb) to 16 (25 at.% Tb).     

Effect of Fish Bone Bioactive Peptides on Oxidative,Inflammatory and Pigmentation Processes Triggered by UVB Irradiation in Skin Cells

In the present study, we evaluated for the first time the photoprotective effect of fish bone bioactive peptides (FBBP) preparation isolated from silver carp (Hypophthalmichthys molitrix) discarded tissue using in vitro experimental models of skin cells exposed to ultraviolet B (UVB) irradiation and stressing agents. FBBP preparation was obtained by papain treatment of minced bones and centrifugal ultrafiltration, and the molecular weight (MW) distribution was characterized by size exclusion and reversed-phase high performance liquid chromatography (RP-HPLC). In vitro assessment of the effect of FBBP pretreatment in UVB-irradiated L929 fibroblasts and HaCaT keratinocytes revealed their cytoprotective activity. Their capacity to efficiently reduce reactive oxygen species (ROS) production and lipid peroxidation varied in a dose-dependent manner, and it was greater in fibroblasts. A decrease of proinflammatory cytokines secretion, in particular of tumor necrosis factor alpha (TNF-α), was found after FBBP pretreatment of THP-1-derived inflamed macrophages. Melanin production and tyrosinase activity investigated in UVB-irradiated Mel-Juso cells were lowered in direct relation to FBBP concentrations. FBBP fractions with high radical scavenging activity were separated by ion exchange chromatography, and two collagenic sequences were identified. All these results offer new scientific data on aquaculture fish bone-derived peptides confirming their ability to control the antioxidant, anti-inflammatory and pigmentation processes developed during UV irradiation of skin cells and recommend their use as valuable natural ingredients of photoprotective cosmeceutical products.