Showing papers by "University of Palermo published in 1987"

A Galerkin approach to boundary element elastoplastic analysis

Abstract: The elastoplastic boundary value problem in terms of rates, formulated using integral equations of linear elasticity, is shown to be amenable, through discretizations, to a linear complementarity problem endowed with a symmetric matrix (in contrast to the traditional boundary element formulation). This symmetrization is achieved by suitably choosing the fundamental solutions and formulating the integral equations for boundary quantities and stresses, and by enforcing in a Galerkin weighted-residual sense (instead of collocation) the boundary integral equations and the plastic constitutive laws over domain cells.

Intra-articular treatment with sodium hyaluronate in gonarthrosis: a controlled clinical trial versus placebo.

Abstract: A double-blind, placebo-controlled study was carried out in 34 patients suffering from osteo-arthritis of the knee. A total of 40 joints was treated at random with 3 intra-articular injections, at 1 week intervals, of either 20 mg sodium hyaluronate or placebo. Clinical examinations, including assessments of spontaneous pain intensity, pain on touch, under load and while walking, were made before each injection and repeated 7 days after the last one and again at 60 days after the start of the trial. The results showed a significant difference between treatments for all the variables assessed. In the sodium hyaluronate group, pain relief was not only rapid but also long lasting. Local tolerance was very good for both treatments.

Q fever in Europe: current aspects of aetiology, epidemiology, human infection, diagnosis and therapy.

Abstract: Il s'agit d'une zoonose. Elle est en general asymptomatique bien que des decouvertes nouvelles aussi bien chez l'homme que chez l'animal mettent en evidence des syndromes cliniques associes en particulier des maladies chroniques graves

Codes and automata

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Oestrogen binding sites in fresh human aortic tissue.

Abstract: Biopsies of aortic tissue were obtained from patients undergoing heart surgery, and were tested for oestrogen binding sites. Tests were carried out using a 7 + 1-point dextran-coated charcoal method, and receptors were quantified both in the cytoplasmic and in the nuclear fractions using Scatchard plot analyses. Tests yielded positive results in 8 cases out of 13 (cytosol fraction) and in 10 cases out of 13 (nuclear fraction). Receptors showed high affinity for oestrogens, the Kd values ranging from 10(-11) M to 10(-10) M. These findings therefore suggest the occurrence of oestrogen receptors in human blood-vessels.

Enthalpies of solution and dilution of butanol and pentanol in dodecyltrimethylammonium bromide micellar solutions

Abstract: The enthalpies of solution and of dilution of 1-butanol and 1-pentanol were measured in micellar solutions of dodecyltrimethylammonium bromide by systematically changing the concentration of alcohols and surfactant. The enthalpies of solution at infinite dilution of alcohols at each surfactant concentration were evaluated from a linear plot. This quantity increases with surfactant concentration (up to 0.8m) with a curvature which depends on the alcohol alkyl chain length. The difficulties arising for a quantitative treatment of both the enthalpies of dilution and of solution at finite alcohol concentrations are discussed. The dependence on the surfactant concentration of the standard enthalpies of solution and the enthalpies of dilution for m→0 are rationalized. From the resulting equations the distribution constant, standard enthalpy of transfer, standard enthalpy of solution, and the alcohol-alcohol interaction parameter in the micellar phase are evaluated. The enthalpies of transfer obtained using this technique agree well with those previously reported from enthalpies of mixing. The distribution constants also agree with those reported in the literature from several approaches: mixing enthalpies, partial molar volumes, and the dependence of the cmc on added alcohol.

Mass-action model for solute distribution between aqueous and micellar phases: mixing enthalpies of alcohols and dodecyltrimethylammonium bromide solutions

Abstract: The mixing enthalpies of aqueous solutions of normal alkanols (from methanol to heptanol) and of dodecyltrimethylammonium bromide were measured taking the enthalpy of dilution of the surfactant solutions as the baseline of the mixing process. The measurements were generally made at a given alcohol concentration by systematically changing the surfactant concentration. In some cases measurements as a function of the alcohol concentration were also carried out. Below the CMC from the mixing enthalpies the pair and the triplet interaction parameters between alcohol and surfactant molecules were calculated. The trend of these parameters as a function of the number of carbon atoms in the alcohol alkyl chain is peculiar in that it is linear for the h RS pair parameter and of an exponential-type for h RSS , whereas the h RRS triplet parameter shows a minimum for butanol. Above the CMC the mixing enthalpies were rationalized using a previously reported model for the alcohol distribution between the aqueous and the micellar phases. From the resulting equation the distribution constant and the transfer enthalpy (and then the standard free energy and entropy) can be obtained at the same time. In the calculation of these quantities the role of the alcohol—surfactant interactions in the aqueous phase and of the displacement of the micellization equilibrium due to the added alcohol is pointed out. As predicted, the additivity rule always holds for the standard free energy of transfer but only holds up to butanol for enthalpy and entropy.

Electropherotype heterogeneity within serotypes of human rotavirus strains circulating in Italy

Abstract: Using solid-phase immune electron microscopy, 126 of 129 human rotavirus (HRV) strains could be serotyped directly in stools collected in Italy during the period 1981–1985. Prevalence was 70.5 per cent for serotype 1, and 13.2 per cent for each of serotypes 2 and 4. No serotype 3 strain was detected. In parallel, for 39 of 61 HRV strains tested the electropherotype of genomic RNA was successfully determined. Different electropherotypes were detected among strains of the same serotype, whereas the same electropherotype was found in HRV strains of different serotypes. Serotyping and electropherotyping of HRV strains appear to be complementary to each other, and both should be used in conjunction for epidemiological surveys.

Excess enthalpies of solution of primary and secondary alcohols in dodecyldimethylamine oxide micellar solutions

Abstract: The excess enthalpies of solution with respect to water of some primary and secondary alcohols in dodecyldimethylamine oxide (DDAO) micellar solutions were measured by mixing aqueous solutions of alcohols with surfactant solutions. Standard free energies, enthalpies and entropies were obtained from the distribution of alcohols between aqueous and micellar phases. It is shown that thermodynamics of transfer of secondary alcohols from aqueous to the DDAO micellar phase differ slightly from those of their corresponding primary alcohols, that the additivity rule holds for free energies of transfer and that enthalpy and entropy display convex curves. The present data are compared with those from the aqueous to the dodecyltrimethylammonium bromide (DTAB) micellar phases and to the literature data for transfer from water to octane. The role of the hydrophilic interactions between OH group and the micellar head groups and of the hydrophobic interactions between the methylene group and its apolar environment is evidenced.

Studies on Holothuria polii (Echinodermata) coelomocyte lysate. I. Hemolytic activity of coelomocyte hemolysins.

Abstract: The Holothuria polii coelomocyte lysate contains two trypsin-resistant lytic proteins having different chemico-physical properties : a calcium dependent and heat-labile hemolysin that is probably a constitutive component of the coelomic fluid, and another calcium independent and heat-stable one that is released after immunological stimulation; it is therefore not detectable in natural conditions. The sphingomyelin seems to be the membrane receptor with which both hemolysins interact producing lysis.

Inhibitory activity of sphingomyelin on hemolytic activity of coelomic fluid of Holothuriapolii (echinodermata)

Abstract: The hemolytic activity of coelomic fluid from Holothuria polii is specifically inhibited by sphingomyelin. This phospholipid is the constituent of the membrane which probably interacts with the hemolysin thereby leading to the lysis.

Littoral Demosponges from the Banks of the Strait of Sicily and the Alboran Sea

Abstract: The material of this study has been collected from the South-Western Mediterranean in the course of two expeditions by the Italian Research Vessel “Bannock”. The primary collection method employed was SCUBA diving. The sampled area is affected by an important inflow of water from the Atlantic. Fifty-nine species have been studied. One of them, Stylostichon equiosculatus, is new to science. Some ecological considerations are also discussed.

Use of strontium isotopes to determine the sources of hydrothermal fluorite and barite from northwestern Sicily (Italy)

Abstract: Fluorite and barite mineralizations outcrop in several localities in the Western Madonie Mts. (NW Sicily, Italy). The still active mineralizing event particularly affected calcareous lithotypes belonging to the Mesozoic formations of the “Termini Imerese facies”. The samples analyzed in this work come from the Poggio Balate area where fluorite and barite seem to be more abundant than in the other localities. These minerals mainly occur in brecciated limestones of Tithonian age. The Sr isotope composition of barite, fluorite and host rocks have been determined. The fluorites show a 87 Sr 86 Sr ratio ranging from 0.70785 to 0.70790, significantly lower than that of the barites, ranging from 0.70861 to 0.70879. This difference suggests that fluorite and barite mineralizations may be the result of two isotopically different fluids. As for fluorite, the bulk of the Sr may have originated from the Tithonian limestones ( 87 Sr 86 Sr ratio range = 0.70752–0.70789), whereas the Miocene-Oligocene Numidian Flysch and Lower Jurassic bedded cherts ( 87 Sr 86 Sr ratio = 0.71646 and 0.72040, respectively) may have been sources of Sr in the barites.

Heat capacities of butanol and pentanol in aqueous dodecyltrimethylammonium bromide solutions

Abstract: Heat capacities of the ternary systems water-dodecyltrimethylammonium bromide (DTAB)-butanol and water-DTAB-pentanol were measured at 25°C. The standard partial molar heat capacities of pentanol in micellar solutions show a maximum at about 0.35 mol-kg−1 DTAB that has been attributed to a micellar structural transition. This maximum tends to vanish by increasing the alcohol concentration and by decreasing the alcohol alkyl chain length; in the case of butanol it was not detected. The behavior of the standard partial molar heat capacities of alcohols in micellar solutions in the region above the cmc and below the structural transition was explained using a previously reported mass-action model for the alcohol distribution between the aqueous and the micellar phase and the pseudophase transition model for micellization. In the resulting equation the contributions due to the temperature effect on the shift of both the micellization equilibrium and the distribution are shown to be negligible so that only the distribution effect and the shift of the micellization equilibrium due to the added alcohol remain. The distribution constant and the partial molar heat capacities of alcohols in the aqueous and micellar phases have been derived by linear regression. The distribution constant for both alcohols agree well with those previously obtained using different techniques. Since the best fit below the structural transition correlates as well with the experimental points above the structural transition, it seems that no difference exists in the standard partial molar heat capacities of alcohols in the two shapes of the micelles. Also, from the present data and those for alkanols in sodium dodecylsulfate reported in the literature it seems that the standard heat capacity of alcohols in the micellar phase does not depend on both the alcohol alkyl chain length and the nature of the hydrophilic moiety of the head group of the micelles.

Soret effect in forced Rayleigh scattering

Abstract: In forced Rayleigh scattering of mixtures or suspensions the temperature gratings generate, by the Soret effect, concentration gratings that may be very important since they produce both a phase and an amplitude grating superimposed on the principal one. The experimental evidence of their influence was given by Thyagarajan and Lallemand using a mixture of carbondisulfide and ethanol. In this paper we study the temporal behaviour of the concentration grating versus the sample properties and its effect on the detected diffracted beam. Explicit expressions are given for the output intensity taking into account both the generated amplitude and phase gratings.

Analysis of F‐wave in metabolic neuropathies: a comparative study in uremic and diabetic patients

Abstract: Motor nerve conduction study along the entire length of the ulnar and tibialis posterior nerves was carried out in 30 diabetics compared with 30 uremic patients and 30 control subjects. The conduction in the proximal and the distal nerve segments was evaluated by the determination of the M and F latencies, MNCV (between the stimulus sites), FWCV (between the spinal cord and the stimulus sites), and F-ratio (conduction time ratio of proximal to distal segment). In both groups of patients the lower limbs appear much more involved than the upper, where the ulnar nerve is more commonly affected in uremic than in diabetic patients. In diabetic neuropathy the motor conduction abnormalities are diffuse over the total length of the nerve, but more marked distally in the ulnar nerve.

.Chromosome sex determination and Y-autosome fusion in Blennius tentacularis Brunnich, 1765 (Pisces, Blennidae)

Abstract: Diploid modal numbers of 2n=48 for females, and 2n=48 and 2n=47 for males of Blennius tentacularis caught in the Gulf of Palermo (Sicily) are established. Chromosome sex-determination is proposed for this species in which a Y-autosome fusion has been found.

Effects of a preparation containing a standardized ginseng extract combined with trace elements and multivitamins against hepatotoxin-induced chronic liver disease in the elderly.

Abstract: A preparation containing a standardized ginseng extract which has been shown to exert anti-hepatotoxic activity in vitro, combined with trace elements and multi-vitamins was compared to placebo in 24 elderly out-patients with toxin-induced (alcohol and drugs) chronic liver disease in order to evaluate its effect on liver function. Each patient was blindly treated either with the preparation containing ginseng extract or placebo for 12 weeks. The preparation containing ginseng extract significantly modified bromsulphthalein retention and blood zinc levels when compared to pre-treatment levels and to placebo. Serum bile acids, and gamma-glutamyl transpeptidase before and after a fatty meal were significantly reduced after treatment with the test preparation and not with placebo. When the two treatment groups were compared, however, no significant difference in these parameters was observed. These results suggest that treatment with the preparation containing ginseng extract could improve the detoxifying activity of the liver in elderly patients with toxin-induced chronic liver disease.