Search

This study focused on the battlements of the Tower of Palazzo Alliata Pietratagliata in Palermo, which is one of the most important examples of late medieval civil architecture in Sicily. The battlements are made by biocalcarenite and currently affected by a strong desegregation. In order to first characterize the stone some tests have been carried out on small samples collected in situ: chemical and morphological analysis through X-ray diffractometry, scanning electron microscopy (SEM), optical polarized light microscopy (PLM), determination of total soluble salt content by measuring the conductivity and dosage of the anions and determination of the dimensional distribution of the pores. The second step was the testing of nanostructured products for the consolidation. Indeed, since for this purpose it was not possible to take the necessary amount of samples directly from the tower, the study proceeded on the limestone of Marsala, intended as the lithotype with structural and textural characteristics similar to the one used in the battlements of the tower. On these stone samples other analyses were performed: determination of bulk (MVA) and real (MVR) density through helium picnometer, water open porosity measurement through the method of the hydrostatic balance, x-ray diffractometry, porosimetry through nuclear magnetic resonance (NMR) relaxometry and scanning electron microscopy (SEM). Moreover, after an induced aging of the specimens for simulating the desegregation of the stone, two nanostructured products for the consolidation, both based on nanosilica, have been applied. Then, two more cycles of diagnostics have been performed in order to understand the effect of the products on the stone. The results obtained through these various experimental techniques are reported and extensively discussed.

Il sempre crescente interesse verso i Beni Culturali suscita molteplici problematiche inerenti la salvaguardia e la diagnosi del loro stato di conservazione. In questo ambito, lo studio delle caratteristiche, quali ad esempio le proprietà capillari delle rocce sedimentarie, ricopre un’importanza cruciale non solo per studiare lo stato di conservazione ma anche per fornire utili indicazioni sulle possibili tecniche e sui materiali da utilizzare negli eventuali trattamenti di protezione e restauro. Al fine di ottenere approfondite informazioni sulle proprietà capillari, il presente lavoro propone un metodo matematico utile nello studio della cinetica di assorbimento capillare. Lo studio è stato condotto su una roccia sedimentaria particolarmente omogenea, la Pietra di Lecce, analizzando le immagini del campione, acquisite mediante la tecnica di imaging NMR (Nuclear Magnetic Resonance, MRI). Il rumore presente nelle immagini è stato ridotto grazie all’utilizzo delle trasformate wavelet. Le immagini elaborate e ricostruite tramite un algoritmo che implementa la trasformata DWT (Discrete Wavelet Transform) – epsilon-decimata, forniscono utili informazioni per la caratterizzazione della cinetica di assorbimento dell’acqua.

In un recente studio condotto mediante Rilassometria NMR del nucleo 1H su legni moderni stagionati è stato mostrato che è possibile separare la curva di rilassamento della componente longitudinale della magnetizzazione nucleare dei nuclei 1H meno mobili (componente “solida”), attribuibili alle macromolecole, da quella dei nuclei a maggior mobilità (componente “liquida”), attribuibili all’acqua. Oltre a permettere di verificare la proporzionalità diretta tra ampiezza della componente liquida del segnale e massa d’acqua, l’analisi delle curve di rilassamento mediante distribuzioni quasi-continue del tempo di rilassamento longitudinale T1 permette di classificare le essenze lignee esaminate, mettendo in evidenza variazioni regolari di tale tempo nel passare da latifoglie a conifere. Alcune regolarità osservate possono essere giustificate assumendo un modello di scambio a due siti, con un tempo di scambio solido-liquido di qualche decina di ms. La stessa analisi, condotta su campioni di legno della statua di San Nicola di Mira (XVI secolo) recentemente restaurata e collocata presso il Museo Diocesano di Palermo, mostra che anche per il legno antico, sebbene fortemente degradato, valgono le stesse regolarità, ma con valori per i tempi di rilassamento e per il tempo di scambio solido-liquido che sono circa la metà di quelli osservati per il legno moderno. Si avanza l’ipotesi che questa accelerazione nei processi di rilassamento e di scambio sia associabile all’aumento del contributo paramagnetico, legato alla presenza di radicali liberi nel legno degradato, messo in evidenza in uno studio parallelo mediante EPR. Per il legno antico trattato non valgono le regolarità osservate per il legno non trattato, sia esso moderno od antico. Le regolarità riscontrate suggeriscono che la Rilassometria NMR possa essere utilizzata in futuro per analisi non distruttive volte alla classificazione delle essenze ed alla diagnosi del degrado di legni di interesse storico-artistico-archeologico.

Ultrasonic absorption spectra have been measured between 0.1 and 2000 MHz of aqueous suspensions of polystyrene latex globules. Samples of different diameter (60 to 100 nm) and different concentration of the polystyrene latex particles (volume fraction between 0.05 and 0.38) have been studied. The broadband spectra exhibit a Debye-type relaxation term in the frequency range around some MHz and a contribution with special characteristics at higher frequencies. The former term is assumed to be due to counterion effects in the surface layer of the globules. No special attention is payed to this effect. The latter contribution is attributed to scattering and mode conversion mechanisms. An approximate explicit and an exact formulation of the theoretical description of the sound wave attenuation by the scattering process are discussed. The explicit formulation enables valuable insights into the mode conversion mechanisms but does not allow for a complete representation of the measured spectra. Application of the exact version leads to the conclusion that in the frequency range under consideration monopole and quadrupole oscillations of the polystyrene latex globules are the dominant cause of ultrasonic wave attenuation. It is found that even at the elevated concentrations used effects of multiple scattering are of minor importance here.

Vengono messe a confronto due tecniche, la Risonanza Magnetica (MRI) e la tomografia assiale computerizzata (TAC), per ottenere informazioni quantitative sulla cinetica di assorbimento dell’acqua in sezioni interne di materiali lapidei. Entrambe le tecniche permettono di studiare adeguatamente il fenomeno. Nel caso in cui si formi un fronte di bagnamento, come per la Pietra di Lecce, l’analisi delle immagini consente di determinare in modo quantitativo l’altezza di risalita in funzione del tempo ed i dati possono essere interpretati alla luce del modello di Washburn per l’assorbimento capillare. Nel caso in cui il fronte non si formi, come per campioni di biocalcareite provenienti da una cava presso la Valle dei Templi di Agrigento, il fenomeno può essere descritto mediante metodi stocastici.

L'efficacia dei trattamenti normalmente impiegati per proteggere e/o consolidare materiali lapidei può essere valutata mediante la tecnica di imaging a risonanza magnetica nucleare (MRI), che consente di studiare in modo quantitativo, non invasivo, non distruttivo, la cinetica di assorbimento capillare dell'acqua. In campioni omogenei (Pietra di Lecce) si forma un fronte piatto (con una discontinuità netta alla scala di misura) e la tecnica MRI permette di seguire la cinetica in quanto consente di misurare, in funzione del tempo, l'altezza raggiunta da tale fronte in qualunque sezione interna del campione. Vengono confrontati i risultati ottenuti sullo stesso litotipo utilizzando due diversi prodotti idrorepellenti. i risultati vengono interpretati alla luce del modello di washburn per l'assorbimento capillare, fornendo parametri utilizzabili per quantificare l'efficacia del trattamento.

La caratterizzazione del legno riveste un particolare ruolo negli studi volti alla conservazione di manufatti lignei di interesse storico-artistico-archeologico. Le proprietà meccaniche del legno dipendono dalla specie, dal contenuto d’acqua, dalla direzione delle fibre, dalla porosità, dalla distribuzione dei pori e, in generale, da un insieme di condizioni che non sempre sono facilmente misurabili e controllabili. Di particolare interesse sono i metodi di indagine non invasivi e non distruttivi; tra questi si sta affermando la Risonanza Magnetica Nucleare (NMR) [1,2]. In questo lavoro metodi di Rilassometria 1H-NMR, messi a punto per il tessuto osseo [3], sono stati applicati allo studio di diverse tipologie lignee. I FID (Free Induction Decay) ottenuti sono la somma di due componenti: una componente approssimativamente gaussiana o “di tipo solido”, ascrivibile alle macromolecole, e una componente esponenziale o “di tipo liquido”, ascrivibile all’acqua. Le curve di distribuzione dei tempi di rilassamento della componente longitudinale della magnetizzazione nucleare dei nuclei 1H, ottenute separatamente per le due componenti in campioni di legno stagionato, mostrano inattese regolarità, che da un lato permettono di classificare i campioni in funzione della specie e dall’altro suggeriscono fenomeni di accoppiamento e/o di scambio tra i nuclei di idrogeno dell’acqua e quelli macromolecolari. Le variazioni dei tempi di rilassamento osservate in campioni degradati possono essere rilevanti nell’ottica della determinazione di parametri atti alla valutazione dello stato conservativo di macromolecole biologiche. Conifera, Latifoglia, Tempi di rilassamento, Macromolecole biologiche [1] A. Maccotta. P. Fantazzini, C. Garavaglia, I. Donato, P. Perzia, M. Brai, F. Morreale, Preliminary 1H NMR study on archaeological waterlogged wood, ANNALI DI CHIMICA 95: 117-124 (2005). [2] A. Maccotta, M. Brai, P. Fantazzini, G. Veronesi, Classificabilità di essenze lignee mediante rilassometria e imaging NMR, XCI Congresso Nazionale SIF, Catania, 26 Sett. – 1 Ott. 2005, p.192. [3] P. Fantazzini, V. Bortolotti, R.J.S. Brown, M. Camaiti, C. Garavaglia, R. Viola, G. Giavaresi, Two 1H-NMR Methods to Measure Internal Porosity of Bone Trabeculae: by Solid-Liquid Signal Separation and by Longitudinal Relaxation, J. Appl. Phys., 95: 339-343 (2004).

In 1H NMR (Nuclear Magnetic Resonance) relaxation measurements for a set of eight hardwood and softwood samples, each Free Induction Decay (FID) is fit by the sum of a “Solid” signal of the form A exp[−c(t/Ts)2] [1−g(t/Ts)2+h(t/Ts)4] plus a “Liquid” signal B exp(−t/T2 FID). Distributions of longitudinal (T1) relaxation times were computed separately for the Solid and Liquid components, giving also the Solid/Liquid 1H ratio α. From measurements on the samples dried, seasoned, and hydrated, the moisture content, (Liquid/Solid weight ratio) was found to be approximately 0.50/α. For each of the “Seasoned” samples (10-13% moisture content) a single T1 peak was found for the Solid and two for the Liquid, with the longer Liquid T1 close to that of the Solid, but with some differences exceeding perceived experimental uncertainties. None of the Solid or Liquid-long T1’s is much less than 20 ms, even though Liquid-short times go as low as 0.35 ms, appearing to negate simple Solid-to-Liquid exchange on a ms time scale. Data for six of the samples (all except for two resin-containing pine species) can be formally fit by a two-site exchange model, in which cases the Solid-to-Liquid exchange times are a few tens of ms. For our set of wood samples, each of the above three T1 values, and also the overall Liquid geometric-mean and rate-average T1’s, as well as the Liquid long-T1 fraction, for a seasoned hardwood is longer than the corresponding value for any softwood, suggesting that relaxation parameters may provide a useful ranking of seasoned woods.

A total of 100 Chinese blood donors (50 from Shen-Zhen and 50 from Taiwan) were studied by the participants in addition to 9 reference samples. A new nomenclature for the CR1 structural alleles was recommended by the participants which would use a numbering system, e.g. CR1*1. The structural allele frequencies in the Chinese were: CR1*1 (190 kD) 0.96, CR1*2 (220 kD) 0.03, CR1*3 (160 kD) 0.01 and CR1*4 (250 kD) 0.00. The HindIII expression polymorphism was also studied and the high expressing allele had a gene frequency of 0.71 while the low expressor gene frequency was 0.28. Erythrocyte copy numbers were quantified and compared between laboratories with good correlation (R = 0.55–0.88). The mean (± SD) erythrocyte copy number was 463 (± 229) in the Taiwan donors and 446 (± 207) in the Mainland Chinese.

This work is addressed to characterize the sedimentary rocks from Sicily used in cultural heritage, classifying them for mineralogical and chemical features as well as for porosity. Measurements on samples collected in Sicilian quarries will be compared with data obtained from micro-invasive techniques on monuments of archaeological interest. In detail, the chosen techniques were X-Ray Diffractometry (XRD), X-Ray Fluorescence (XRF), Magnetic Resonance Relaxometry (MRR), Magnetic Resonance Imaging (MRI). Furthermore, adsorption kinetics studies and internal microporosity surveys on samples, both through X-ray tomography, are performed. Many of sedimentary rocks (common limestones, calcarenites, travertines, etc.) have been used for the building of archaeological-historical items of Sicily, from Magna Graecia to nowadays. The final aim is the understanding of the deterioration processes and the eventual remedial actions to prevent the decay of the cultural heritage. In particular, our attention was focused on building materials used for some of the temples of Agrigento, Segesta and Selinunte.

Recently measured broadband ultrasonic spectra of binary mixtures of water with various monohydric alcohols are discussed with respect to precritical behaviour of the liquids. It is shown that the frequency-dependent excess absorption can indeed be empirically represented by a very few parameters if a special relaxation function is used. Moreover, the coupling of the acoustic field to the heterogeneous structure can be alternatively considered

The nonlinear relation between stimulus intensity and response amplitude of the electroretinogram (ERG) scotopic b wave can be described by a curve based on the Naka-Rushton (NR) equation. Up to now, the NR equation has been used to assess the features of the normal and pathological ERG, but the best approach for a correct evaluation of the parameters is still debatable. The parameters are thought to be related to the different conditions of retinal activities. The method is well known in experimental laboratories but is quite unusual at the clinical level. In the present paper the derivative analysis of the NR function is proposed as an easier approach to understand the variations of the NR parameters in selected pathologies.

Ultrasonic absorption spectra have been measured between 150 kHz and 1.6 GHz for mixtures of water with ethanol, the propanol isomers, and all isomers of butanol at 25 {degrees}C. With the exception of the systems exhibiting a miscibility gap (n-butanol isobutyl alcohol, sec-butyl alcohol), the measurements have been performed over the complete composition range. Various relaxation functions have been fitted to the measured spectra, among them such reflecting stoichiometrically well-defined chemical reactions and, alternatively, functions based on conception of fluctuations in the composition of the binary liquids. The frequency dependent excess absorption of the complete set of mixtures can be well represented assuming a sum of a Debye-type term with discrete relaxation time and a Fixman-Kawasaki term. The latter reflects a distribution of relaxation times as resulting from concentration fluctuations including critical behavior. The parameters of these relaxation terms are discussed to yield information on the underlying molecular mechanisms. One result is the finding of the fluctuation correlation length in the completely miscible systems to not exceed some molecular diameters. This result is important for our ideal of the molecular behavior of these liquids. It is also relevant to our discussion of frequency-dependent measurements of nuclear magnetic relaxation rates andmore » also of dielectric spectroscopy. 90 refs., 10 figs., 6 tabs.« less

HLA haplotypes, complement C4 factor and factor B immonochemical concentrations and autoantibodies titer have been studied in six patients with mild congenital adrenal hyperplasia (MC-AH), in two patients with classical congenital adrenal hyperplasia (CCAH) and in their parents. A high frequency of DR5 and C4BQO alleles have been found in MCAH patients. Moreover, C4BQO allele is carried out in three out of four cases associated with DR5. In the two CCAH patients we found a B51 and a B14 allele, the last one usually described in the non classical form of the disease in population of different ethnic origin. Signs of autoimmunity in some patients and parents have been found. C4 null alleles were several-fold more frequent among our patients with respect to the same ethnic control group and the autoantibody positivity could be the result of an altered immune regulation. The presence of a positive correlation between Cortisol basal levels and C4 and Bf concentrations in the six MCAH patients suggests an interrelationship between hormonal factors and immunological findings in this disease. Our finding about HLA antigens not previously described in this syndrome may stimulate more profound studies by genomic and cDNA probes.

SUMMARYTwo sensitive sandwich ELISAs based on monoclonal antibodies directed to native C6 and C7 allowed the detection and quantitation of these complement proteins in 20 out of 37 serum samples from individuals who had previously been classified as deficient in these proteins as assessed by immunochemical and/or functional assays. Furthermore, serum from four C6-deficient and one combined C6-/C7-deficient individual showed an increase in the terminal complement complex (TCC) and a decrease in native C6 and C7 after complement activation as assayed by specific ELISAs. Despite their (incomplete) deficiencies, these individuals therefore possess functionally active terminal complement proteins with respect to their ability to generate the TCC. As these individuals have no history of a susceptibility to neisserial infections, even low concentrations of functionally active C6 and C7 may provide sufficient protection against those micro-organisms whose destruction requires TCC formation.

At 25°C the ultrasonic absorption coefficient and the sound velocity of dimethyl sulfoxide/water mixtures have been measured for various mole fractions between 0 and 1. The measurements of the absorption coefficient have been performed as a function of frequency between 200 kHz and 2.75 GHz. The sound velocity has been determined by three methods at different frequencies of the above range. At given mole fraction the absorption per wavelength increases linearly with frequency and the sound velocity is constant. Thus no relaxation process is found which could be attributed to the suggested formation of stoichiometrically well-defined dimethyl sulfoxide/water complexes. The volume viscosity and the adiabatic compressibility are derived from the measured quantities. The dependence upon the mixture composition is discussed together with other ones to show that there are special mixture properties at mole fractions around 30 % dimethyl sulfoxide. The mixtures, however, seem to be homogeneous hydrogen-bonded networks rather than being composed of definite molecular complexes.

The Electroretinogram (ERG) is a composite signal reflecting the complex response of the retinal different parts. It is known that the rod and cone systems contribute to this response. The most used method to analyze the data is the study of the b-wave amplitude and peak time change against the intensity of the stimulus theoretically investigated by an approach based on a simplified picture of a single responding photoreceptorial population in scotopic or photopic condition. The aim of the present paper is to investigate the dependence of the amplitude and the implicit time of the a- and b-wave of the ERG on the input luminance level to obtain hints devoted to recognize the different contribution to the response of the two systems, rods and cones, in normals and pathological subjects.

A glow curve analysis has been carried out to study the response of some LiF dosimeters when irradiated by radiations with different LET. The aim of the study was to have a better understanding of the role of material characteristics in determining their glow curve response when irradiated with 60Co gamma rays and proton beams. Glow curves for TLD-100 and GR-200 LiF dosimeters have been analyzed and deconvolution of the peak structure has been performed within the frame of first order kinetics.