Showing papers by "University of Palermo published in 1996"

A Controlled Trial of Two Acellular Vaccines and One Whole-Cell Vaccine against Pertussis

Abstract: Background Concern about both safety and efficacy has made the use of whole-cell pertussis vaccines controversial. In some European countries, including Italy, the rate of vaccination against pertussis is low. Methods We conducted a double-blind trial in Italy in which infants were randomly assigned to vaccination at two, four, and six months of age with an acellular pertussis vaccine together with diphtheria and tetanus toxoids (DTP); a DTP vaccine containing whole-cell pertussis (manufactured by Connaught Laboratories); or diphtheria and tetanus toxoids without pertussis (DT). The acellular DTP vaccine was either one containing filamentous hemagglutinin, pertactin, and pertussis toxin inactivated with formalin and glutaraldehyde (SmithKline Beecham) or one with filamentous hemagglutinin, pertactin, and genetically detoxified pertussis toxin (Chiron Biocine). Pertussis was defined as 21 days or more of paroxysmal cough, with infection confirmed by culture or serologic testing. Results The efficacy of eac...

Comparison of the Photoelectronic and Photocatalytic Activities of Various Anatase and Rutile Forms of Titania in Pure Liquid Organic Phases and in Aqueous Solutions

Abstract: Various titania samples of industrial origin (Degussa and Tioxide) have been characterized by electrical photoconductance measurements and tested as photocatalysts in various liquid media (either pure organic liquids or aqueous solutions) as a function of their structure (anatase versus rutile). Anatase was constantly found more active than rutile, whatever the reaction chosen (mild oxidation of pure cyclohexane and 2-propanol; total degradation of phenol and nitrophenol isomers in water). In identical conditions, Degussa was found more active, but the intrinsic activity, expressed in moles converted per hour and per square meter of active surface, was found slightly higher for anatase Tioxide. The higher activity of anatase with respect to that of rutile could be explained by the interpretation of the photoconductance measurements, which evidence the higher aptitude of anatase (i) to photoadsorb oxygen, in O2- and O- forms; (ii) to photodesorb it; and (iii) to have a lower relative electron−hole recombin...

Design of Nonionic Surfactants for Supercritical Carbon Dioxide

Abstract: Interfacially active block copolymer amphiphiles have been synthesized and their self-assembly into micelles in supercritical carbon dioxide (CO2) has been demonstrated with small-angle neutron scattering (SANS). These materials establish the design criteria for molecularly engineered surfactants that can stabilize and disperse otherwise insoluble matter into a CO2 continuous phase. Polystyrene-b-poly(1,1-dihydroperfluorooctyl acrylate) copolymers self-assembled into polydisperse core-shell-type micelles as a result of the disparate solubility characteristics of the different block segments in CO2. These nonionic surfactants for CO2 were shown by SANS to be capable of emulsifying up to 20 percent by weight of a CO2-insoluble hydrocarbon into CO2. This result demonstrates the efficacy of surfactant-modified CO2 in reducing the large volumes of organic and halogenated solvent waste streams released into our environment by solvent-intensive manufacturing and process industries.

Noise enhanced stability in an unstable system.

Abstract: We experimentally detect noise enhanced stability in an unstable physical system. The average escape time from a metastable, periodically driven, system is measured in the stable and unstable regimes in a noisy environment. In the unstable regime, we measure that the average escape time has a maximum for a finite value of the noise intensity. The scaling properties of the average escape time and of the variance of escape times are compared with the predictions obtained for a system in a marginal state.

Gastroesophageal reflux and cow's milk allergy in infants: A prospective study

Abstract: Background: Recent reports have suggested that gastroesophageal reflux in pediatric patients may be caused by food allergy. Objective: The aim of our study was to determine the frequency of the association of gastroesophageal reflux with cow's milk protein allergy in patients in the first year of life. Methods: We studied 204 consecutive patients (median age, 6.3 months) who had been diagnosed as having gastroesophageal reflux on the basis of 24-hour continuous pH monitoring and histologic examination of the esophageal mucosa. Results: Clinical history suggested diagnosis of cow's milk allergy in 19 infants, and 93 others had positive test results (serum IgE anti-lactoglobulin, prick tests, circulating or fecal or nasal mucus eosinophils) but did not have symptoms indicating cow's milk allergy. The cow's milk-free diet and two successive blind challenges confirmed the diagnosis of cow's milk allergy in 85 of the 204 patients with gastroesophageal reflux. The clinical presentations of the infants with gastroesophageal reflux alone were different, in view of the greater frequency of diarrhea (p Conclusions: Considering the frequency of this association, patients younger than 12 months old with symptoms of gastroesophageal reflux should be carefully examined to determine whether this disorder is primary or caused by cow's milk allergy.

Black Hole Binaries and X-Ray Transients

Abstract: We consider transient behavior in low-mass X-ray binaries (LMXBs) We show that if this results from a disk instability, the secondary star must be significantly evolved when mass transfer starts, particularly if the primary is a neutron star For P 2 days, most neutron star systems will be persistent X-ray sources, whereas the slower orbital evolution of black hole systems means that most of them are likely to be transient Both types of transient system must have extreme mass ratios (<01) For orbital periods P 2 days, most LMXBs will be transient regardless of whether the primary is a neutron star or a black hole

The parkes Southern pulsar Survey — I. Observing and data analysis systems and initial results

Abstract: 'Australia Telescope National Facility, CSIRO, PO Box 76, Epping NSW 2121, Australia Wuffield Radio Astronomy Laboratories, University of Manchester, lodrell Bank, Macclesfield, Cheshire SKII 9DL 3Istituto di Radioastronomia del CNR, Via Gobetti 101, 40129 Bologna, Italy 4Istituto di Fisica dell'Universita, Via Archirafi 36, 90123 Palermo, Italy 'Research Centre for Theoretical Astrophysics, University of Sydney, NSW 2006, Australia 6Mount Stromlo and Siding Spring Observatories, Australian National University, Private Bag, Weston ACT 2611, Australia

Cytokine production pathway in the elderly

Abstract: It is well known that aging is associated with various alterations in lymphoid cell functions, particularly with a progressive decline in immune responsiveness to exogenous antigens and increasing incidence of autoimmune phenomena. Many studies have been focused on the mechanisms of the immunologic features of aging. this review describes our results of studies performed to determine the influence of age on the capacity to produce interleukin-2 (IL-2), interferon-gamma (IFN-gamma), interleukin-4 (IL-4), interleukin-t (IL-5), interleukin-6 (IL-6) and tumor necrosis factor (TNF). Mitogen-stimulated cultures of mononuclear cells (MNC) from human beings were assessed for cytokine-producing capacity. A significant decrease in IFN-gamma and IL-2 production by MNC cultures from elderly individuals was observed. No significant difference was instead observed between cultures from elderly individuals and those from young ones as regards TNF-alpha, IL-4 and IL-6 production. Mitogen or antigen-stimulated cultures of MNC from aged mice also displayed a significant decrease in IFN-gamma and IL-2 production as well as TNF-beta. Instead IL-4 and IL-5 production significantly increased in these cultures. We suggest that this imbalanced cytokine production may well account for the pattern of immune response which may be observed in the elderly, i.e. a normal or increased humoral response (including autoimmune responses) in face of a low T cell immune responsiveness.

Microalbuminuria, renal dysfunction and cardiovascular complication in essential hypertension.

Abstract: ObjectiveTo evaluate the prevalence of microalbuminuria (albumin excretion rate, AER) in a wide hypertensive population, and to evaluate any relationship with cardiovascular damage and renal dysfunctionDesignA transversal studySubjects and methodsIn 383 hospitalized Caucasian essential hypertensives

Monadic second-order logic over rectangular pictures and recognizability by tiling systems

Abstract: It is shown that a set of pictures (rectangular arrays of symbols) is recognized by a finite tiling system iff it is definable in existential monadic second-order logic. As a consequence, finite tiling systems constitute a notion of recognizability over two-dimensional inputs which at the same time generalizes finite-state recognizability over strings and also matches a natural logic. The proof is based on the Ehrenfeucht–Fraisse technique for first-order logic and an implementation of “threshold counting” within tiling systems.

Release of transforming growth factor-beta (TGF-beta) and fibronectin by alveolar macrophages in airway diseases.

Abstract: Asthma and chronic bronchitis are associated with airway remodelling, and airway macrophages are present in bronchial inflammation. TGF-β and fibronectin released by alveolar macrophages possess a fibrogenic potency. The potential role of alveolar macrophages in airway remodelling was studied in asthma and chronic bronchitis by the release of TGF-β and fibronectin. Alveolar macrophages were isolated by bronchoalveolar lavage in 14 control subjects, 14 asthmatics and 14 chronic bronchitics. The spontaneous and lipopolysaccharide (LPS)- or concanavalin A (Con A)-induced release of TGF-β and fibronectin was measured by ELISA. Alveolar macrophages from chronic bronchitics spontaneously release greater amounts of TGF-β and fibronectin than those from asthmatic and control subjects. Alveolar macrophages from asthmatics release greater amounts of TGF-β and fibronectin than those from control subjects. The spontaneous release of TGF-β is significantly correlated with that of fibronectin. Fibronectin release was significantly reduced after LPS stimulation, and TGF-β release was significantly increased after LPS stimulation, except in chronic bronchitis patients. Con A increased the release of TGF-β in cells from normal subjects. This study suggests that activated macrophages play a role in airway remodelling in chronic bronchitis and to a lesser extent in asthma.

Asthma after consumption of snails in house‐dust‐mite‐allergic patients: a case of IgE cross‐reactivity

Abstract: A group of 28 patients from Italy was studied who had asthma after consumption of snail. All patients also had asthma and/or rhinitis caused by house-dust mite. RAST analyses confirmed the combined sensitization to snail and mite. In a few sera, IgE antibodies reactive with other foods of invertebrate origin (mussel and shrimp) were detected. RAST inhibition showed that most IgE antibodies against snail were cross-reactive with house-dust mite. In contrast, the mite RAST was not significantly inhibited by snail. This indicates that house-dust mite was the sensitizing agent. Immunoblot analyses revealed multiple bands in snail extract recognized by IgE. In contrast to what has been described for cross-reactivity between shrimp and mite, tropomyosin played only a minor role as a cross-reactive allergen in these patients. The observations in this study indicate that snail consumption can cause severe asthmatic symptoms in house-dust-mite-allergic patients. It might, therefore, be advisable to screen mite-allergic asthma patients for allergy to snail and other invertebrate animal foods.

Selective hydrogenation of acetylene in ethylene feedstocks on Pd catalysts

Abstract: Pumice supported palladium catalysts were compared with Pd SiO 2 and Pd Al 2 O 3 in the hydrogenation of acetylene using typical industrial ethylene feedstocks: front-end and tail-end cuts. Pd/pumice catalysts exhibit good activity and excellent selectivity and stability in the title reaction. Their activity/selectivity pattern is controlled by the composition of the reaction mixture. The turnover frequency (TOF) increases, and the apparent activation energy (Ea) decreases, with the H 2 C 2 H 2 ratio, but they are not affected by the C 2 H 2 C 2 H 4 ratio. The selectivity to ethane (SE) does not change with acetylene conversion at low H 2 C 2 H 2 ratio (tail-end cut) and increases at high H 2 C 2 H 2 ratio (front-end cut). No dependence of SE with acetylene conversion was found, at any H 2 C 2 H 2 ratio, on varying the metal dispersion. TOF and SE change with metal loading depending on the reaction mixtures; low metal loaded catalysts gave the best activity/selectivity pattern. Pd/pumice catalysts do not show aging phenomena even when used in drastic conditions (high space velocities and front-end cuts). The catalytic behavior of Pd/pumice catalysts, as a function of the composition of reaction mixture, elucidated by using the isokinetic relationship (IKR) approach shows that the relative amount of hydrogen in the feedstocks plays an important role in activation/deactivation processes which occurs on the metal surface. By considering the presence of different centers on the catalyst and by performing data analysis with a suitable mathematical model, the microscopical mechanism and the role of surface deposits can be explained. A similar reaction mechanism is applicable to the other palladium catalysts, at least in the case of tail-end mixtures.

Zero Energy Rotating Accretion Flows near a Black Hole

Abstract: We characterize the nature of thin, axisymmetric, inviscid, accretion flows of cold adiabatic gas with zero specific energy in the vicinity of a black hole by the specific angular momentum. Using two-dimensional hydrodynamic simulations in cylindrical geometry, we present various regimes in which the accretion flows behave distinctly differently. When the flow has a small angular momentum $(\lambda\lsim\lambda_b)$, most of the material is accreted into the black hole forming a quasi-spherical flow or a simple disk-like structure around it. When the flow has a large angular momentum (typically, larger than the marginally bound value, $\lambda\gsim\lambda_{mb}$), almost no accretion into the black hole occurs. Instead, the flow produces a stable standing shock with one or more vortices behind it and is deflected away at the shock as a conical outgoing wind of higher entropy. If the flow has an angular momentum somewhat smaller than $\lambda_{mb}$ $(\lambda_{u}\lsim\lambda\lsim\lambda_{mb})$, a fraction (typically, $5-10$\%) of the incoming material is accreted into the black hole, but the the flow structure formed is similar to that as for $\lambda\gsim\lambda_{mb}$. Some of the deflected material is accreted back into the black hole, while the rest is blown away as an outgoing wind. These two cases with $\lambda\gsim\lambda_u$ correspond those studied in the previous works by Molteni, Lanzafame, \& Chakrabarti (1994) and Ryu \etal (1995). However, the flow with an angular momentum close to the marginally stable value $(\lambda_{ms})$ is found to be unstable. More specifically, if $\lambda_b\lsim\lambda\sim\lambda_{ms}\lsim\lambda_u$, the flow displays a distinct periodicity in the sense that the inner part of the disk is built and

The effect of complementary irrigation on fruit growth, ripening pattern and oil characteristics of olive (Olea europaea L.) cv. Carolea

Abstract: SummaryComplementary irrigation, 80 mm, distributed only during the third stage of fruit development, delayed ripening time and increased fruit size and oil content for fruits of the olive cv. Carolea. Prolonged water deficit reduced fruit growth, oil accumulation rate, K content of the fruit and enhanced ripening and pre-harvest fruit drop. Harvest time affected oil characteristics more than the water availability. Fatty acid composition was not affected by the water regime but polyphenol content increased and alcohol content decreased in the oil produced by irrigated trees.

Self-regulation mechanism of an ecosystem in a non-Gaussian fluctuation regime.

Abstract: We study a dynamical model for an ecological network of many interacting species We consider a Malthus-Verhulst type of self-regulation mechanism In the framework of the mean field theory we study the nonlinear relaxation in three different cases: (a) towards the equilibrium state, (b) towards the absorbing barrier, (c) at the critical point We obtain asymptotic behavior in all different cases for the time average of the process The dynamical behavior of the system, in the limit of infinitely many interacting species, is investigated in the stability and instability conditions and theoretical results are compared with numerical simulations \textcopyright{} 1996 The American Physical Society

Intrasinusoidal bone marrow infiltration: a possible hallmark of splenic lymphoma.

Abstract: A particular type of lymphomatous bone marrow infiltration defined as intrasinusoidal and occuring in seven patients with splenomegaly and mild to moderate thrombocytopenia is reported. Immunocytochemistry highlighted the intrasinusoidal pattern and showed a mature B-cell phenotype. Four patients underwent splenectomy and a diagnosis of splenic marginal cell lymphoma was made. The disease course seems to be chronic and quite indolent. All patients are alive and well ; follow-up ranges from 2 to 42 months. The value of bone marrow biopsy as a primary diagnostic tool in splenic marginal zone lymphomas is discussed.

Interferon as treatment for acute hepatitis C : A meta-analysis

Abstract: The efficacy of short-course (three months), low-dose (3 million units three times a week) interferon as treatment for acute hepatitis C was evaluated in a meta-analysis of controlled trials. Nine studies (five randomized and four nonrandomized) found by MEDLINE search were eligible for analysis. The outcomes assessed were the rate of patients with normal serum aminotransferases (all trials) and without HCV RNA in blood (five trials) after posttreatment follow-up. Eight trials compared interferon to no treatment, and one compared different schedules of interferon. The methodological quality of the studies was high. However, all trials had been planned for a short-term evaluation based on biochemical and virological outcomes alone. Significant differences were observed between interferon and control groups for both the assessable end points. Overall rate differences were +0.31 (P < 0.0001; 95% confidence interval +0.20 to +0.41) for aminotransferases normalization and +0.44 (P < 0.0001; 95% confidence interval +0.33 to +0.56) for HCV RNA clearance. In conclusion, a short course of low-dose interferon administered to patients with acute hepatitis C is significantly more effective than no treatment in obtaining viral clearance and normal aminotransferases 12 months after stopping treatment. Further long-term prospective cohort studies assessing outcomes of clinical relevance (ie, the rate of chronicity of infection and disease) are necessary before recommending interferon for acute hepatitis C.