Evaluation of the effect of cleaning on the morphological properties of ancient paper surface

In the conservation field, the original morphology and texture of the paper surface represent an important aspect to be preserved as historical evidence of the papermaking process. The aim of this preliminary research is to evaluate the effects of aqueous (cellulose ethers, rigid gels of Agar and Gellan gum) and not aqueous cleaning treatments (a typical dry cleaning treatment with wishab sponge) on the original surface morphology of late nineteenth century paper. Nineteenth century newspaper paper was chosen because it is strongly affected by cellulose oxidation and depolimerization due to the rough materials (wood pulp) and the papermaking process used at the time and to the environmental conditions (light, humidity, temperature) to which such paper has been subjected. A preliminary characterization of the paper with Herzberg and Phloroglucinol reactives and Fourier Transform infrared Spectroscopy analysis was performed to understand the paper composition and the type of inorganic fillers used. The paper surface microtopography was then measured by contact profilometry to analyze the effects of the cleaning treatments on paper surface roughness. The effects of the cleaning action was qualitatively evaluated by means of stereo microscopy and scanning electron microscopy. Preliminary results suggest that the treatments which are most respectful of the original surface micromorphology of the paper are those based on the use of rigid gels (Agar and Gellan gum), because they determine the smallest variation in the roughness of surface paper, unlike the application of cellulose ethers by brush. This finding was confirmed by statistical analysis of the roughness results by means of ANOVA and Tukey HSD post hoc test.     

Synthesis of New Cytosine and Thymine Derivatives of Potential Immunomodulatory Activity

The synthesis and the main chemical and physical properties of some N¹alkylated cytosines and thymines are described.     

Electroanalytical Method for Determining Pyrogallol in Biodiesel in the Presence of a Surfactant

A sensitive, straightforward electroanalytical method for determining pyrogallol (PY) in biodiesel in the presence of a surfactant was developed using a voltammetric technique and screen‐printed electrodes. The influence of surfactant addition (sodium dodecyl sulfate (SDS), Triton X‐100 (TX‐100), cetyltrimethylammonium bromide (CTAB), tetrabutylammonium iodide (TBAI), tetrabutylammonium bromide (TBAB), or tetraethylammonium bromide (TEAB)) on the supporting electrolyte (0.04 mol L^?1 Britton? Robinson buffer) was evaluated. Only CTAB significantly increased the oxidation peak current. Under optimal conditions, the method demonstrated linearity over the concentration range of 0.8–9.0×10^?6 mol L^?1, with limits of detection and quantification of 4.9×10^?7 and 1.5×10^?6 mol L^?1, respectively. The results were satisfactory, relative to those obtained using high‐performance liquid chromatography (HPLC).     

Direct conversion of polyconjugated compounds into their corresponding carboxylic acids by Acetobacter aceti

The conversion of polyconjugated aldehydes or alcohols into their corresponding acids was carried out using Acetobacter aceti. The analytical results were compared with those of the acids chemically obtained using a Horner-Wittig reaction.     

A note on stability for parametric equilibrium problems

In this paper we consider equilibrium problems in vector metric spaces where the function f and the set K are perturbed by the parameters ε,η. We study the stability of the solutions, providing some results in the peculiar framework of generalized monotone functions, first in the particular case where K is fixed, then under both data perturbation.     

A comparison of numerical integration rules for the meshless local Petrov–Galerkin method

The meshless local Petrov–Galerkin (MLPG) method is a mesh-free procedure for solving partial differential equations. However, the benefit in avoiding the mesh construction and refinement is counterbalanced by the use of complicated non polynomial shape functions with subsequent difficulties, and a potentially large cost, when implementing numerical integration schemes. In this paper we describe and compare some numerical quadrature rules with the aim at preserving the MLPG solution accuracy and at the same time reducing its computational cost.     

Ultraviolet four-photon mixing in a multimode silica fiber Raman amplifier

Efficient frequency conversion of the XeF excimer (351.2 nm) by nonlinear effects in a highly multimode silica fiber is reported. Besides a substantial Raman amplification of the weaker XeF line at 353.3 nm, stimulated four-photon mixing has also been observed, generating a Stokes peak at 355.5 nm with 1 kW peak power.     

Temperature renormalization of the magnon energies of FeBr2

The temperature renormalization of the magnon energies is investigated in FeBr₂, a S = 1 Heisenberg ferromagnet with rather large single-ion and exchange anisotropies. Two theories are applied: a self-consistently-renormalized (SCR) spin-wave theory (which is not affected by “kinematic” inconsistencies) and a calculation of the self-energy in the T-matrix formalism. At low temperature both theories are found to give a small renormalization of the energy gap in agreement with neutron scattering experiments. On the other hand the two approximations give significantly different renormalization at higher temperature. Measurements in this temperature range should be able to put in evidence non linear effects in the anisotropy.