Auditory evoked responses: A tool to assess the fetal neurological activity

An intact auditory system at birth is requisite for the successful accomplishment of many developmental skills. Evoked responses to auditory stimuli have been used as a sensitive test to determine the functional status of the adult and neonatal brain. It has been established that fetuses can hear in utero and respond to external acoustic stimuli. We present an overview of the transmission of sound through the maternal abdomen to the fetal ear and the recordings of an auditory evoked response obtained from the fetus using a non-invasive magnetoencephalography technique. The investigation of cortical activity of the fetus in response to auditory stimulation can help understand and track the neurological development of the fetus.     

Fabrication of "hairy" colloidosomes with shells of polymeric microrods

Novel colloidosome microcapsules with aqueous gel cores and integral shells of rodlike polymeric particles have been prepared and characterized. The synthesis is based on templating water-in-oil emulsions stabilized by rodlike particles followed by gelling of the aqueous phase, dissolution of the oil phase in ethanol, and redispersion of the obtained colloidosome capsules in water. Such capsules may find applications as vehicles for delivery and controlled release of drugs, cosmetics, and food supplements.     

The domain of partial attraction of a Poisson law

Groshev gave a characterization of the union of domains of partial attraction of all Poisson laws in 1941. His classical condition is expressed by the underlying distribution function and disguises the role of the mean of the attracting distribution. In the present paper we start out from results of the recent probabilistic approach and derive characterizations for any fixed >0 in terms of the underlying quantile function. The approach identifies the portion of the sample that contributes the limiting Poisson behavior of the sum, delineates the effect of extreme values, and leads to necessary and sufficient conditions all involving . It turns out that the limiting Poisson distributions arise in two qualitatively different ways depending upon whether >1 or <1. A concrete construction, illustrating all the results, also shows that in the boundary case when =1 both possibilities may occur.     

Non-arrhenius behavior of the island density in metal heteroepitaxy: Co on Cu(001)

We present a combined theoretical and experimental study of island nucleation and growth in the deposition of Co on Cu(001)-a prototype for understanding heteroepitaxial growth involving intermixing. Experimentally, ion scattering is employed. Using density-functional theory, we obtain energy barriers for the various elementary processes and incorporate these into a kinetic Monte Carlo program to simulate the heteroepitaxial growth. Both the simulations and the experiments show a unique N-shape dependence of the island density on temperature that stems from the interplay and competition of the different processes involved.     

Correlation-driven charge order at the interface between a Mott and a band insulator

To study digital Mott insulator LaTiO3 and band insulator SrTiO3 interfaces, we apply correlated band theory within the local density approximation including a Hubbard U to (n, m) multilayers, 1相似文献   

Multiple tandem mass spectrometry-based investigation of the behaviour of some thiazol-benzimidazolones and 2-benzimidazolylsulfanyl ethanones

The behaviour in electrospray conditions of a series of thiazol-benzimidazolones and 2- benzimidazolylsulphanyl ethanones has been studied by means of multiple tandem mass spectrometry experiments. Even though the experimental conditions were the same, different behaviour is observed for the two classes of compounds. In the case of thiazol-benzimidazolones, the formation of a protonated complex with CH3OH employed as solvent is observed, but in the case of 2-benzimidazolylsulphanyl ethanones the formation of MNa+ ions is privileged. This behaviour has been related to molecular structure. The collisionally-induced decompositions of MH+ ions have been rationalised in terms of the Stevenson-Audier and even-electron rules, as well as on the basis of proton affinity data. Thus, protonated thiazol-benzimidazolones undergo facile loss of CO and a series of different decomposition pathways involving cleavage of the thiazolone ring that reflect the structure of the neutral fragments. In contrast, the decompositions of the protonated 2-benzimidazolylsulphanyl ethanones are mainly related to the piperazine moiety, suggesting that the protonation takes place on this substructural unit.     

Coefficient identification in Euler-Bernoulli equation from over-posed data

A method for solving the inverse problem for coefficient identification in the Euler-Bernoulli equation from over-posed data is presented. The original inverse problem is replaced by a minimization problem. The method is applied to the problem for identifying the coefficient in the case when it is a piece-wise polynomial function. Several examples are elaborated and the numerical results confirm that the solution of the imbedding problem coincides with the direct simulation of the original problem within the second order of approximation.     

Density functional theory study of water adsorption on FeOOH surfaces

Using density functional theory (DFT) calculations with an on-site Coulomb repulsion term, we study the composition, stability, and electronic properties of the most common FeOOH surfaces goethite(101), akaganeite(100), and lepidocrocite(010), and their interaction with water. Despite the differences in surface structure, the trends in surface stability of these FeOOH polymorphs exhibit remarkable similarities. We find that the reactivity and the binding configuration of adsorbates depend strongly on the coordination of surface iron: at the fourfold coordinated Fe2 site water is chemisorbed, whereas at the fivefold coordinated Fe1 water is only loosely bound with hydrogen pointing towards the surface. Our results show that the oxidation state of surface iron can be controlled by the surface termination where ferryl (Fe^4 +) species emerge for oxygen terminated surfaces and ferrous iron (Fe^2 +) at iron and water terminations leading to a reduced band gap. In contrast, the fully hydroxylated surfaces, identified as stable surface configurations at standard conditions from the surface phase diagram, show electronic properties and band gaps closest to bulk FeOOH with ferric surface iron (Fe^3 +). Only in the case of goethite(101), a termination with mixed surface hydroxyl and aquo groups is stabilized.     

Synergistic Effects of Co and Fe on the Oxygen Evolution Reaction Activity of LaCoxFe1−xO3

In a combined experimental and theoretical study we assess the role of Co incorporation on the OER activity of LaCo_xFe_1−xO₃. Phase pure perovskites were synthesized up to in 0.025/0.050 steps. HAADF STEM and EDX analysis points towards FeO₂-terminated (001)-facets in LaFeO₃, in accordance with the stability diagram obtained from density functional theory calculations with a Hubbard U term (DFT+U). Linear sweep voltammetry conducted in a rotating disk electrode setup shows a reduction of the OER overpotential and a nonmonotonic trend with x, with double layer capacitance measurements indicating an intrinsic nature of activity. This is supported by DFT+U results that show reduced overpotentials for both Fe and Co reaction sites with the latter reaching values of 0.32–0.40 V, ∼0.3 V lower than for Fe. This correlates with a stronger reduction of the binding energy difference of the *O and *OH intermediates towards an optimum value of 1.6 eV for , the OH deprotonation being the potential limiting step in most cases. Significant variations of the magnetic moments of both surface and subsurface Co and Fe during OER demonstrate that the beneficial effect is a result of a concerted action involving many surrounding ions, which extends the concept of the active site.     

Viscosity measurements of water at high temperatures and pressures using dynamic light scattering

The application of dynamic light scattering to measure viscosity of water at high temperatures and pressures is demonstrated. Viscosity was obtained from the translational diffusion coefficient of probe particles dispersed in the medium by the Einstein-Stokes relationship. Measurements were carried out with polystyrene latex, colloidal silica, and colloidal gold. Under a constant pressure of 25 MPa, good agreement was found between the measured and calculated viscosities up to 275 degrees C with the polystyrene latex, 200 degrees C with the colloidal silica, and 297 degrees C with the colloidal gold. It was found that failure of the measurements at high temperatures is ascribed to change in either the dispersion stability or chemical stability of the probe particles. The present results indicate that the technique could also be used for other supercritical fluids having high critical temperature and pressure, such as methanol (T(c) = 239.4 degrees C, P(c) = 8.1 MPa) and ethanol (T(c) = 243.1 degrees C, P(c) = 6.4 MPa).