Lowest energy electronic transition in aqueous Cl(-) salts: Cl(-) → (H2O)6 charge transfer transition

We use UV resonance Raman spectroscopy to probe the lowest energy allowed electronic transitions of aqueous solutions containing Cl(-) salts. We show that the waters hydrating the Cl(-) are involved in charge transfer transitions that transfer electron density from Cl(-) to the water molecules. These charge transfer transitions cause significant change in the H-O-H bond angle in the excited state, which results in a strong enhancement of the preresonance Raman intensity of the water bending modes. Our work gives the first insight into the lowest allowed electronic transition of hydrated Cl(-).     

Dynamic flow in a realistic model of the upper human lung airways

The objective of the study is an analysis of lung ventilation during breathing under rest conditions and for high frequency ventilation (HFV). The measurements include investigations of the flow using an endotracheal tube. A transparent model of the upper human lung airways down to the 6th generation was generated, and the oscillatory flow through the branching network was studied by DPIV. The method of refractive index matching of the fluid (water/glycerin) and the model (silicone) allows an unobstructed view into the internal flow network. The mass flow rate and the frequency were adapted to the characteristic flow parameters, the Reynolds- and the Womersley-number. The comparison of the results for normal breathing and HFV shows that a mass exchange occurs for higher frequencies known as Pendelluft, which could not be seen during normal breathing. This mass exchange between the daughter tubes is a consequence of the asymmetric impedance in the successive daughter branches. The lung topology determines the local pressure loss in the model and therefore the local mass flow direction of the Pendelluft. At higher frequencies we observed an increase in exchange between the daughter branches. The transformation of the velocity profiles between inspiration and expiration suggests a net mass flow which is created into the model along the centerline and the inner walls of the bifurcations. This flow is compensated with a net mass outflow to the trachea along the outer walls of the branches.     

What's Wrong with These Observables?

An imprecise measurement of a dynamical variable (such as a spin component) does not, in general, give the value of another dynamical variable (such as a spin component along a slightly different direction). The result of the measurement cannot be interpreted as the value of any observable that has a classical analogue.     

Synthesis and characterization of stimuli‐sensitive micro‐ and nanohydrogels based on photocrosslinkable poly(dimethylaminoethyl methacrylate)

The aim of this work was the development of a versatile route for the preparation of temperature‐ and pH‐responsive hydrogels with small dimensions. The copolymerization of N,N‐dimethylaminoethyl methacrylate with various amounts (5 and 10 mol %) of dimethylmaleimidoethyl methacrylate in solution with 2,2′‐azobisisobutyronitrile as an initiator is described. The structural and molecular characterization of the copolymers was performed with proton nuclear magnetic resonance, Fourier transform infrared, and ultraviolet spectroscopy, as well as size exclusion chromatography. Differential scanning calorimetry and thermogravimetry were used for the thermal characterization of the copolymers. Micro‐ and nanohydrogels of the copolymers were prepared by photocrosslinking. The gels obtained by photocrosslinking were characterized with a combination of surface plasmon resonance and optical waveguide spectroscopy, dynamic light scattering, and scanning electron microscopy. The hydrogels showed temperature‐ and pH‐responsive behavior. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 669–679, 2007     

Majoration des tensions dans un corps élastique à l'aide des déplacements superficiels

Sans résumé Mémoire présenté par G. Fichera Cet ouvrage a été accompli durant que l'auteur jouissait d'une bourse de l'Institut National de Mathématique Supérieure de Rome.