Influence of pressure, temperature and gas phase composition on biacetyl laser-induced fluorescence

The purpose of this work is to get fundamental knowledge and to understand experimentally the fluorescence phenomenon usually used in laser-based imaging diagnostics. A complete review of thermodynamic effects (pressure, temperature, oxygen and tracer concentration) on biacetyl fluorescence is presented for a wide range of temperature and pressure. Biacetyl fluorescence increases with pressure and then levels off at high pressure when the relaxation is complete. The influence of the temperature is explained by a competition between the intersystem crossing and fluorescence. The effect of oxygen fluorescence quenching is important at high pressure and is discussed.     

Graphs of finite mass which cannot be approximated in area by smooth graphs

In this note we shall show that there are obstructions of homotopic and not just of homological nature to the approximability in area of graphs of finite mass by graphs of smooth maps. We shall present a class of closed graphs with finite mass which cannot be approximated weakly and in area by smooth graphs. This work has been partially supported by the Ministero dell'Universitá e della Ricerca Scientifica, by C.N.R. contract n. 91.01343.CT01, and by the European Research Project GADGET     

Remarks on the lower semicontinuity of quasiconvex integrals

We prove lower semicontinuity of quasiconvex integrals with integrands controlled by the minors.This work has been partially supported by the Ministero dell'Università e della Ricerca Scientifica and by the European Research Project GADGET II     

Few constraints limit the design of quinone methide-oligonucleotide self-adducts for directing DNA alkylation

Nucleotide sequences minimally containing adenosine, cytosine or guanosine are sufficient to form intrastrand oligonucleotide quinone methide self-adducts reversibly for subsequent alkylation of complementary DNA. The general lack of sequence restrictions should now allow for alkylation of most any target of interest although reaction is most efficient when the self-adducts contain guanine residues and do not form hairpin structures.     

Area and the area formula

Conferenza tenuta da Mariano Giaquinta il 28 settembre 1992     

Nonlinear Stochastic Homogenization

Sunto In questo lavoro viene studiata l'omogeneizzazione stocastica per funzionali integrali del Calcolo delle Variazioni con integrando dipendente dalla variabile spaziale e convesso nel gradiente, soddisfacente alle usuali ipotesi di uniforme coercitività e limitatezza. Il risultato generale ottenuto copre un largo spettro di fenomeni riguardanti materiali con disposizione casuale di più componenti il cui comportamento fisico è retto da equasioni variazionali non lineari.     

A general and stereoselective route to alpha- or beta-galactosphingolipids via a common four-carbon building block

A general synthetic strategy toward alpha- or beta-galactosylceramides and their analogues from 3-azido-2-O-benzyl-1-O-(4-methoxybenzyl)butane-1,2,4-triol is described. The key steps for the installation of the main lipid chain are either a diasteroselective alkynylation reaction yielding the 4R stereocenter of phytosphingosine or a Wittig olefination generating the trans double bond of sphingosine. The methodology allows the preparation of different glycolipids with variations in the structure of the sphingoid base. In particular, three alpha-GalCer-related compounds have been synthesized and evaluated for their ability to activate CD1d-restricted T-cells.