Characterisation of fresh and aged terpenic resins by micro-FTIR and GC-MS analyses of varnishes in XVI-XVII centuries paintings

Resinous materials, generally added to drying oils, were often employed as final protective films in paintings, both in tempera and oil techniques. Most of the resins used in fine arts come from exudates of plants. Natural resins are mainly composed by terpenoids. Among these resins, dammar, rosin, mastic, elemi gum, Venice turpentine were frequently employed in easel paintings. The aim of this work is the identification of natural resins in samples collected from works of art. In this paper we propose to use micro-FTIR spectrometry as a preliminary and non destructive technique to detect the presence of resinous materials in microsamples collected from paintings, followed by GC-MS analyses to obtain a precise identification of the resin. To reach this aim commercial resins, employed as standard, were analysed previously by micro-FTIR spectrometry and then analysed by GC-MS chromatography, searching characteristic chemical compounds used as "markers" of resins. The results obtained on standards allowed us to successfully analyse samples collected from two works of art: the "Portrait of a Young Gentleman", by Lorenzo Lotto (XVI century), and the "Madonna with the Infant Jesus and Saints": by Carlo Maratta (XVII secolo).     

Synthesis of 1-(4-substituted)benzyl-6-hydroxyisoquinolines with potential activity on NA+,K+-atpase

The synthesis of 1-(4-substituted)benzyl-6-hydroxyisoquinolines, to be evaluated in the displacement of the specific ³H-ouabain binding to Na⁺,K⁺-ATPase, is described. The key step involved a cyclization to the isoquinoline ring under Pictet-Gams conditions which was best performed with the 6-hydroxy group protected as the benzyl ether. When an unsaturated ester group was present in position 4 of the 1-benzyl group, this was best introduced before the cyclization step, since the IIeck reaction on 1-(4-bromobenzyl)-6-hydroxyisoquinoline ( 8 ) with acrylic acid derivatives was not successful in all cases.     

Synthesis of new polycyclic systems containing the pyrimido[2,1-a]phthalazine skeleton

The synthesis of new polyheterocycles containing the pyrimido[2,1-a]phthalazine system 5, 6 and 7 , obtained by condensation of phthalic anhydride with the appropriate hydrazides 2, 3 and 4 , respectively, are reported. It was also synthesized the 14H-[1]Benzothieno[3′,2′:4,5]pyrimido[2,1-a][1,2,4]triazolo[4,3-c]phthalazin-14-one (16).     

A fast procedure to immobilize polyethylene glycols in glass capillary columns

Polyethylene glycols can be immobilized in glass capillary columns by a new procedure involving covering the glass walls with a layer of graphitized carbon black and by flowing a mixture of the stationary phase and dicumyl peroxide. After curing and conditioning the column is ready for use. Excellent performance is reported for Carbowax 20 M and high molecular weight glycols. For other glycols the immobilized layer is less stable and can be washed out.     

The effect of composition of parenteral solution on the thermal resistance of Bacillus stearothermophilus and Bacillus subtilis spores

Large-volume parenteral solutions were submitted to heat treatments after being inoculated with Bacillus stearothermophilus ATCC 7953 (T _r =121°C) and Bacillus subtilis ATCC 9372 (T _r =104.5°C) spores. The average decimal reduction time for B. stearothermophilus ranged from a D _121°C value of 1.31 to 3.14 min, in glucophysiologic and Ringer’s solutions respectively. For B. subtilis, D _104.5°C value increased from 0.69 to 1.37 min, in Ringer’s (pH=5.91) and 50% glucose (pH 3.05) solutions respectively. The z value ranged from 7.95°C (20% mannitol solution) to 13.14°C (50% glucose solution), corresponding to an activation energy (Ea) of 81.48 and 49.30 kcal/mol, respectively.     

Transition state localization by a density functional method. Applications to isomerization and symmetry-forbidden reactions

Summary A new transition state algorithm incorporated into the density functional code deMon, has been used to study thetrans cis-hydroxymethylene andtrans-hydroxymethylene formaldehyde isomerization processes and to localize the transition state for the decomposition of 1,3-diazacyclobutane to methyleneimine. Calculations have been performed using both local (LSD) and nonlocal spin density (NLSD) gradient-corrected approximations. Two different basis sets of small and large size have been used for the study in order to analyze the effect of the basis set dimension other than that of the nonlocal corrections on the activation energy barrier value. The results seem to confirm that density functional methods can be considered practical and reliable tools for the localization of transition states.     

Gauge theory of fermions onR × S 3 spacetime

A Lorentz-invariant gauge theory for massive fermions on R × S ³ spacetime is built up. Using the symmetry of S ³,we obtain Dirac-type equation and derive the expression of the fermionic propagator. Finally, starting from the SU(N) gauge-invariant Lagrangian, we obtain the set of Dirac-Yang-Mills equations on R × S ³ spacetime, pointing out major differences from the Minkowskian case.     

The Dunford-Pettis Property for some Function Algebras in Several Complex Variables

The Dunford-Pettis property is shown to hold for the uniformalgebra A() and its dual for some standard domains , includingstrongly pseudoconvex bounded domains in Cⁿ, pseudoconvex boundeddomains of finite type in C², and bounded domains in C. Previouslythe result was known for the unit ball and unit polydisc inCⁿ. Techniques used involve Bourgain algebras, Hankel operators,properties of the Bergman kernel, quasi-metrics on the boundary,and -theory.