The Lipopolysaccharide from Capnocytophaga canimorsus Reveals an Unexpected Role of the Core-Oligosaccharide in MD-2 Binding

Capnocytophaga canimorsus is a usual member of dog's mouths flora that causes rare but dramatic human infections after dog bites. We determined the structure of C. canimorsus lipid A. The main features are that it is penta-acylated and composed of a “hybrid backbone” lacking the 4′ phosphate and having a 1 phosphoethanolamine (P-Etn) at 2-amino-2-deoxy-d-glucose (GlcN). C. canimorsus LPS was 100 fold less endotoxic than Escherichia coli LPS. Surprisingly, C. canimorsus lipid A was 20,000 fold less endotoxic than the C. canimorsus lipid A-core. This represents the first example in which the core-oligosaccharide dramatically increases endotoxicity of a low endotoxic lipid A. The binding to human myeloid differentiation factor 2 (MD-2) was dramatically increased upon presence of the LPS core on the lipid A, explaining the difference in endotoxicity. Interaction of MD-2, cluster of differentiation antigen 14 (CD14) or LPS-binding protein (LBP) with the negative charge in the 3-deoxy-d-manno-oct-2-ulosonic acid (Kdo) of the core might be needed to form the MD-2 – lipid A complex in case the 4′ phosphate is not present

Ab initio Investigation to Model Stilbene Photo-Physical Properties by Combining CC2 Topological Investigation and CASPT2 Energy Corrections

Stilbene photoexcitation and consequent decay to the ground state has been investigated by mapping the Minimum Energy Path (MEP) from S1 spectroscopic state triggering an almost barrierless reaction pathway to an S1/S0 degenerate region. The particular influence of the σ‐π excitation on the S1 wave function, dominated by a π→π* character, reveals how the non‐dynamical correlation energy was important to correctly describe the excited state behaviour and the topological aspect of its potential energy surface. Several strategies of calculations, by using CASSCF//CASPT2 methods, were performed trying to improve the photochemical description nowadays known. Both symmetry and non symmetry preserving computations were performed; systematically was concluded that, because of the limit of CASSCF description enables only to introduce the correlation effect such as the ones due to σ‐π excitations, CASSCF and CASPT2 topologies are probably often not in agreement. Thus CC2 methodology was adopted o optimize the S1 geometries and obtain reasonable structures for the minima. Two S1/S0 accessible conical intersections featured by pyramidalized carbons were located on the first excited state explaining the ultrafast radiationless decay to the ground state and the photoproducts observed within the timescale of ps

Equivalenza di significato tra condizionali e disgiunzioni.

la ricerca si propone di indagare sperimentalmente la relazione di significato tra condizionali fattuali e frasi disgiuntive. Tale relazione è discussa anche in logica, in quanto in grado di discriminare tra diversi modelli dei condizionali. Anche in psicologia, la relazione tra condizionali e disgiuntive ha una ricaduta sulle diverse teorie del ragionamento con condizionali. In particolare, quali sono i fattori che influenzano la percezione della relazione di significato tra condizionali e le disgiunzioni che secondo la logica classica sono equivalenti

COBRAMM (part 2): an Overview on Some Computational Details; Geometry Optimization, Frequency Calculation, Analysis of the Results

This contribution illustrates some features of a new of a newly implemented general hybrid approach. This method, included in the COBRAMM (Computations at Bologna Relating Ab‐initio and Molecular Mechanic Methods) suite of programs, has a modular structure that integrates some specialized programs and represents a flexible computational environment that increases the flexibility/efficiency of QM, and MM, and QM/MM calculations. Here we describe some aspects of the geometry optimization procedure and explain some approximations used in the frequency computation. Moreover we present two analysis procedures that allow to rank the contribution of the various aminoacid residues of an enzyme in determining the catalytic mechanism and the shape of a Potential Energy Surface (PES)

Developing a Simulated Environment to Study Naturalistic Decision Making Processes

Motivation – Combination of qualitative and quantitative methodologies to develop a simulated environment to study decision-making processes from a NDM perspective. Research approach – Discourse analysis to find interpretative repertoires, use of Visual Analog Scales and ANOVA to validate the reportoires. Findings/Design – Usefulness of qualitative and quantitative methodologies to develop the simulation, importance of a rigorous validation. Research limitations/Implications – Need for comparison with a real website in further studies. Originality/Value – Use of NDM perspective to investigate processes that were studied just from a DM perspective. Take away message – It is possible to study decision-making processes by naturally simulating them, with computer mediated technology, in a laboratory

COBRAMM: A Tunable QM/MM Approach to Complex Molecular Architectures. Modelling the Excited and Ground State Properties of Sized Molecular Systems

This contribution describes a new implementation of a general hybrid approach with a modular structure (called COBRAMM: Computations in Bologna Relating Ab‐initio and Molecular Mechanics Methods) that is able to integrate some specialized softwares and acts as a flexible computational environment, thus increasing the flexibility/efficiency of both QM, and MM, and QM/MM calculations. Specifically, QM/MM ground and excited states geometry optimizations, frequency calculations, conical intersection searches and adiabatic/non‐adiabatic molecular dynamics can be performed on a large molecular system, that can be split up to three different layers corresponding to different levels of accuracy. Here we report, together with a description of the method and its implementation, some test examples on very different chemical problems, which span the wide and diversified area of chemistry (from ground to excited states topics) and show the flexibility, general applicability and accuracy of the presented hybrid approach in the modelling of complex molecular architectures