Some remarks on Bayesian inference for one-way ANOVA models

We consider the standard one-way ANOVA model; it is well-known that classical statistical procedures are based on a scalar non-centrality parameter. In this paper we explore both marginal likelihood and integrated likelihood functions for this parameter and we show that they exactly lead to the same answer. On the other hand, we prove that a fully Bayesian testing procedure may provide different conclusions, depending on what is considered to be the real quantity of interest in the model or, said differently, which are the competing hypotheses. We illustrate these issues via a real data example.     

UV-vis spectra of <Emphasis Type="Italic">p</Emphasis>-benzoquinone anion radical in solution by a TD-DFT/PCM approach

Excited electronic states of the anion radical of para-benzoquinone were studied by time dependent density functional theory (TD-DFT) including bulk solvent effects by the polarizable continuum model (PCM). The computed vertical excitation energies for the first four low-lying doublet states are in good agreement with previous post-Hartree–Fock computations. Geometry optimization of excited states and inclusion of solvent effects lead to a remarkable agreement between computed adiabatic transition energies and experimental band maxima. Together with their specific interest, the results point out the reliability of TD-DFT/PCM approach for valence excitations and the need to take geometry relaxation and solvent effects into the proper account for a meaningful comparison between computed and experimental absorption spectra.     

A new synthetic route to tyromycin A and its analogue from renewable resources

The synthesis of tyromycin A and that of the non-natural lower homologue, involving as featuring steps a transition metal catalyzed atom transfer radical cyclization and a functional rearrangement of the polyhalogenated 2-pyrrolidinones thus obtained, are described. Both routes use 10-undecenoic acid, a renewable source from castor oil, as starting material for the preparation of the pivotal intermediates α,α,α′,α′-tetrachlorodicarboxylic acids.     

Theory of oxides surfaces, interfaces and supported nano-clusters

Oxides surfaces and thin films are finding continuous new technological applications and represent an important class of systems in materials science. Today we assist to a considerable effort to characterize the surfaces and the interfaces of oxide materials at an atomistic level. The intense experimental activity in this field has stimulated a parallel computational activity based on high-quality first principle calculations. In this review we focus our attention on the properties of oxide surfaces, and we describe the main factors that contribute to determine their behaviour: (1) nature of the bonding and electronic structure of the oxide; (2) surface morphology and defectivity; (3) doping and functionalization; (4) redox properties; (5) nano-dimensionality (e.g. in ultra-thin films). We also show how each of these parameters can affect the properties of supported metal atoms and nano-particles.     

A new technique for the measurement of the product CO/CO2 ratio at the surface of char particles burning in a fluidized bed

A new experimental technique is proposed to measure the product CO/CO₂ ratio at the surface of spherical char particles during fluidized bed combustion. It is based on the measurement of the burning rate of a single char particle under low oxygen concentration conditions and on the use of an accurate prediction of the particle Sherwood number. This technique was applied to spherical char particles obtained from a bituminous coal which is characterized by a low attrition and fragmentation propensity. The product CO/CO₂ ratio was measured at a bed temperature of 850 °C and at a fluidization velocity of 0.3 m/s in a lab-scale apparatus operated with a bed of 0.5–0.6 mm sand. The char particle size was varied between 2 and 7 mm and the inlet oxygen concentration between 0.1% and 2.0%. Results showed that under the experimental conditions investigated carbon was mostly oxidized to CO₂ within the particle boundary layer, with a maximum fraction of carbon escaping as CO of 10–20% at the lowest oxygen concentrations and largest particle sizes.     

The longitudinal changes of BOLD response and cerebral hemodynamics from acute to subacute stroke. A fMRI and TCD study

Background  

By mapping the dynamics of brain reorganization, functional magnetic resonance imaging MRI (fMRI) has allowed for significant progress in understanding cerebral plasticity phenomena after a stroke. However, cerebro-vascular diseases can affect blood oxygen level dependent (BOLD) signal. Cerebral autoregulation is a primary function of cerebral hemodynamics, which allows to maintain a relatively constant blood flow despite changes in arterial blood pressure and perfusion pressure. Cerebral autoregulation is reported to become less effective in the early phases post-stroke.     

A highly sensitive radial diffusion measurement method for white matter tract investigation

This article describes a novel approach for local estimation of the radial diffusion coefficient (D(perpendicular)) in white matter (WM) regions containing well-oriented nervous fibers. The method is based on the assumption that the diffusion process in well-organized WM regions responds to a cylindrical symmetry. The increased precision in the estimation of D(perpendicular) provided by this local approach compared to standard techniques based on diffusion tensor imaging is demonstrated using numerical simulations. An in vivo validation of the technique is also provided, showing its application to the corpus callosum of six healthy volunteers, highlighting the sensitivity of the method. Assuming that D(perpendicular) is sensitive to myelin integrity, our technique has the potential to investigate pathophysiological aspects of several neurological and psychiatric disorders with improved precision in targeted WM tracts.     

NMR Characterization of Ethylene/Propylene Copolymers and Propylene Impact Copolymers from MgCl2/TiCl4/ID+AlR3/ED Catalytic Systems

Summary: The aim of this work was to study the comonomer distribution and the chemical composition distribution generated by different Ziegler-Natta (ZN) systems (different internal donors, ID, dicyclopentadienyl-dimethoxy silane, D donor, as the external donor) and to define the potentialities of different IDs to produce improved heterophasic copolymers (HECO). A methodology to quantify the amount of ethylene-propylene copolymer (EP) portion in ZN-HECO and ethylene content of the EP portion by ¹³C-NMR was established. By using this method, it was possible to analyze the composition of ZN-HECO obtaining results comparable to those obtained with a more complex fractionation technique.     

Molecular‐Dynamics‐Simulation‐Directed Rational Design of Nanoreceptors with Targeted Affinity

Here, we demonstrate the possibility of rationally designing nanoparticle receptors with targeted affinity and selectivity for specific small molecules. We used atomistic molecular‐dynamics (MD) simulations to gradually mutate and optimize the chemical structure of the molecules forming the coating monolayer of gold nanoparticles (1.7 nm gold‐core size). The MD‐directed design resulted in nanoreceptors with a 10‐fold improvement in affinity for the target analyte (salicylate) and a 100‐fold decrease of the detection limit by NMR‐chemosensing from the millimolar to the micromolar range. We could define the exact binding mode, which features prolonged contacts and deep penetration of the guest into the monolayer, as well as a distinct shape of the effective binding pockets characterized by exposed interacting points.     

FE analysis of the in-plane mechanical properties of a novel Voronoi-type lattice with positive and negative Poisson’s ratio configurations

This work presents a novel formulation for a Voronoi-type cellular material with in-plane anisotropic behaviour, showing global positive and negative Poisson’s ratio effects under uniaxial tensile loading. The effects of the cell geometry and relative density over the global stiffness, equivalent in-plane Poisson’s ratios and shear modulus of the Voronoi-type structure are evaluated with a parametric analysis. Empirical formulas are identified to reproduce the mechanical trends of the equivalent homogeneous orthotropic material representing the Voronoi-type structure and its geometry parameters.