Showing papers by "University of Naples Federico II published in 1985"

Aluminum alloy structures

Abstract: This book examines the ways in which aluminium and its alloys satisfy the requirements of civil engineering structures and the applications in which they compete with steel. The first edition has become known as an authoritative design reference book on the subject. As a result of the author's continuing research in the field, the new edition is th

Escherichia coli S-adenosylhomocysteine/5'-methylthioadenosine nucleosidase. Purification, substrate specificity and mechanism of action.

Abstract: S-Adenosylhomocysteine/5'-methylthioadenosine nucleosidase (EC 3.2.2.9) was purified to homogeneity from Escherichia coli to a final specific activity of 373 mumol of 5'-methylthioadenosine cleaved/min per mg of protein. Affinity chromatography on S-formycinylhomocysteine-Sepharose is the key step of the purification procedure. The enzyme, responsible for the cleavage of the glycosidic bond of both S-adenosylhomocysteine and 5'-methylthioadenosine, was partially characterized. The apparent Km for 5'-methylthioadenosine is 0.4 microM, and that for S-adenosylhomocysteine is 4.3 microM. The maximal rate of cleavage of S-adenosylhomocysteine is approx. 40% of that of 5'-methylthioadenosine. Some 25 analogues of the two naturally occurring thioethers were studied as potential substrates or inhibitors of the enzyme. Except for the analogues modified in the 5'-position of the ribose moiety or the 2-position of the purine ring, none of the compounds tested was effective as a substrate. Moreover, 5'-methylthioformycin, 5'-chloroformycin, S-formycinylhomocysteine, 5'-methylthiotubercidin and S-tubercidinylhomocysteine were powerful inhibitors of the enzyme activity. The results obtained allow the hypothesis of a mechanism of enzymic catalysis requiring as a key step the protonation of N-7 of the purine ring.

Differential cross-section of high-mass muon pairs produced by a 194 GeV/c π− beam on a tungsten target

Abstract: We present a measurement of the production of muon pairs in 194 GeV/c π−-tungsten interactions. A sample of 155,000 events with mass higher than 4.07 GeV/c2 has been used to determine the differential cross-section as a function of the scaling variables\(\sqrt \tau \) andxF.

Effect of water on the properties of epoxy matrix and composite

Abstract: The complex sorption behavior of the water in amine-epoxy thermosets is discussed and related to depression of the mechanical properties. The hypothesized sorption modes and the corresponding mechanisms of plasticization are discussed on the basis of experimental vapor and liquid sorption tests, differential scanning calorimetry (DSC), thermomechanical analysis (TMA) and dynamic mechanical analysis. In particular, two different types of epoxy materials have been chosen: low-performance systems of diglycidyl ether of bisphenol-A (DGEBA) cured with linear amines, and high-performance formulations based on aromatic amine-cured tetraglycidyldiamino diphenylmethane (TGDDM) which are commonly used as matrices for carbon fiber composites.

On natural thinking

Abstract: (1985). On natural thinking. European Journal of Science Education: Vol. 7, No. 2, pp. 133-140.

Observation of anomalous scaling violation in muon pair production by 194 GeV/c π−-tungsten interactions

Abstract: The differential cross-section for dimuon production by 194 GeV/c π− onW, as measured by the NA10 Collaboration, is compared with theoretical models. The wide kinematical range of the data, extending well above the ϒ resonances, provides the opportunity of a comparison with ‘realistic’ Drell-Yan models, i.e. with those allowing for scaling violation in the hadronic structure functions. The data in fact clearly indicate the failure of the ‘naive’ Drell-Yan model, while the available ‘realistic’ versions (leading logarithm approximation and next-to-leading logarithm approximation in first order QCD), although giving a better description of the data, still disagree in thexF and\(\sqrt \tau \) dependences of the cross-section at high dimuon masses. This disagreement is referred to here as ‘anomalous’ scaling violation. The dependence of the results on external inputs (nucleon and pion-sea structure functions) is analysed; it is shown that in the next-to-leading logarithm approximation the value 〈K〉=1.03±0.03 (stat.) can be obtained for the ratio experimental/theoretical cross-section.

Characterization of the morphological fine structure of commercial thermosetting resins through hygrothermal experiments

Abstract: This review collects some of the recent advancements and significative investigations on the sorption behaviour and moisture sensitivity of a class of widely utilized and investigated thermosetting resins: the epoxy systems In the last few years complete studies on the diffusion of moisture in thermosets have revealed that complex sorption behaviours are often a consequence of dominant modes of sorption driven by structural and chemical differences The diffusional transport of small amount of penetrant below the polymer glass transition may be described by the classical theory, even though the system is not purely viscous fluid mixture Often, however, the relative movements of polymer and solvent can be affected by the rearrangement of the polymer morphology, leading to a history dependent diffusional transport, denoted as viscoelastic diffusion Meaningful penetrant diffusion coefficients and equilibrium solubilities may be obtained from ordinary sorption tests if experiments are conduceted so that viscoelastic diffusion is avoided

Different glycaemic responses to pasta, bread, and potatoes in diabetic patients.

Abstract: To evaluate whether the same amount of carbohydrate (CHO) in different foods gives different glycaemic responses when consumed in the context of a real meal, seven diabetic patients were given in a random order and on alternate days three test meals of identical composition. Each meal consisted of a fixed part to which a 50 g CHO portion of either bread (90 g) or spaghetti (65 g) or potatoes (285 g) was added. The glycaemic response was significantly higher after ingestion of bread than after the spaghetti meal both at 2 (5.9 +/- 0.8 vs 4.3 +/- 0.7 mmol/l X hour, p less than 0.05) and at 5 hours (16.5 +/- 3.6 vs 9.8 +/- 2.3 mmol/l X hour, p less than 0.05). The glycaemic response to the potato meal was similar to that for bread at 2 hours (6.2 +/- 1.2 mmol/l X hour, p less than 0.05 vs spaghetti) and intermediate between the two other test meals at 5 hours (14.6 +/- 4.3 mmol/l X hour). Meal planning for diabetic patients should be based not only on the biochemical properties but also on the glycaemic response to the food.

Clinical course and outcome of schizoaffective disorders. A three-year follow-up study.

Abstract: Four samples of patients (fulfilling at the index episode, respectively, Research Diagnostic Criteria for schizoaffective disorder manic type, schizoaffective disorder depressed type, manic disorder and major depressive disorder) were followed up for 3 years. At the end of the follow-up period, no significant difference with respect to the mean scores on the Disability Assessment Schedule (DAS) and on the Strauss-Carpenter Outcome Scale was observed between schizomanics and manics (although the global outcome was slightly poorer in the former group). In contrast, significant differences between schizodepressives and depressives were found both on some DAS subscales (the schizodepressives were more socially withdrawn, had less social contacts and poorer work performance) and on the Strauss-Carpenter Outcome Scale (the mean total score and the mean scores on the items "social contacts" and "employment" were significantly lower in schizodepressives). The most frequent pattern of course in patients diagnosed cross-sectionally as schizomanic was a bipolar one. Some patients had only recurrent schizomanic episodes and others more an alternance of schizomanic and schizophrenic episodes. In patients diagnosed cross-sectionally as schizodepressives, the most frequent pattern of course was that characterized by recurrent schizodepressive episodes. In some patients an alternance of schizodepressive and depressive or schizodepressive and schizophrenic episodes was observed. These data confirm that patients diagnosed cross-sectionally as schizoaffective represent a very heterogeneous group when they are studied longitudinally, and support the usefulness of a "multiaxial" approach to the classification of schizoaffective disorders, taking into account both cross-sectional symptomatology and clinical course.

Space Science and Applications

Abstract: The exploitation of the present tethered system and the need for repeat missions; multiple payloads placed along the tether; the extension of the present altitude limit to below 130 km; the development of free-flying tether satellites for studying both the Earth's atmosphere and ionosphere and also for studying the plantes; and a subtether were discussed. Areas of research were identified: aeronomy studies, gravity and magnetic potential mission, advanced sensors for geodynamics, and mapping and remote sensing.

Surgical management of acute cerebellar infarction

Abstract: After reviewing the literature, a personal series of 10 adult patients with cerebellar infarction diagnosed by CT scan is described. The clinical picture in young adult men is characterized by rapid onset of headache, vomiting, vertigo, ataxia and blurred vision. After this sudden onset the patients may present a stable course or a rapid or delayed onset of brain stem compression, revealed by impairment of consciousness. CT scan is the diagnostic method of choice. The correlation between angiographic and CT localization of the infarction is not good. For therapy the following policy is suggested: in alert and clinically stable patients: medical treatment (mannitol, glycerol, dexamethason), ICP and serial CT monitoring; in alert patients with hydrocephalus or mass effect: medical treatment and monitoring as mentioned before; ventricular drainage if ICP surpasses 350 mm H2O; in patients with impaired consciousness and hydrocephalus or mass effect: immediate ventricular drainage. If it is not followed by prompt improvement of the level of consciousness, an emergency suboccipital craniectomy with removal of the infarcted tissue should be done.

Chromosomal Aberrations Induced by Elf Electric Fields

Abstract: Bovine lymphocytes in McCoy culture medium and autologous plasma were exposed to 50 Hz 2.4 µA/cm2 current density. Chromosomal aberrations (breaks, aneuploidy, ployploidy, deletions, fragments) were significantly increased in exposed cultures. The number of sister chromatid exchanges was unchanged.

A Unilateral Model for the Limit Analysis of Masonry Walls

Abstract: In this paper the collapse of masonry walls is examined. For the masonry material a constitutive elastic model with zero tensile strength is assumed. The existence of solutions of the elastic equilibrium problem is analyzed and a definition of the collapse condition is provided. The corresponding kinematical and statical theorems, for the evaluation of the collapse load, are established.

An approach to the diagnosis and classification of schizoaffective disorders for research purposes.

Abstract: A classification of schizoaffective disorders for research purposes is presented. Two main categories are preliminarily singled out: 1) that characterized by the consecutive appearance of an affective and a schizophrenic syndrome (type I), 2) that marked by the concurrent appearance of a full schizophrenic and a full affective syndrome (type II). Within type I, two subtypes are distinguished: 1) that beginning as a typical schizophrenic disorder and shifting later on into a recurrent affective syndrome (affective subtype), 2) that beginning as an affective disorder and showing in its further course a progressive schizophrenic development towards deterioration (schizophrenic subtype). For type II, a multiaxial classification is proposed. Axis 1 should be used to describe the cross-sectional symptomatology, axis 2 to define the course, and axis 3 to note the presence of associated factors. On axis 1, schizoaffective disorder type II can be divided into a manic and a depressive subtype. Operational diagnostic criteria for each are provided. On axis 2, an affective (recurrent) and a schizophrenic (continuous with exacerbations) subtype can be distinguished.

X-ray microanalytical studies on cryofixed blood cells of the ascidian Phallusia mammillata. I. Elemental composition of morula cells.

Abstract: Cryofixed blood morula cells of Phallusia mammillata (Cuvier), which are considered to be vanadium-accumulating cells, were examined by X-ray microanalysis using STEM (scanning transmission electron microscopy) and SEM (scanning electron microscopy). It is thought that cryopreparation preserves the native distribution of diffusible elements such as sodium, chlorine, and potassium, and prevents the displacement of vanadium, all of which may occur during conventional preparation. The results show that morula cell globules contain a large amount of sulphur and chlorine, and some sodium, magnesium, bromium and potassium, but very little or no vanadium.

Antihypertensive and cardiovascular effects of nitrendipine: a controlled study vs. placebo.

Abstract: The antihypertensive and cardiovascular effects of nitrendipine, a calcium entry blocker similar to nifedipine, have been evaluated in a double-blind, placebo-controlled study in 20 patients with hypertension. At baseline and at the end of the 8-week period (nitrendipine, 20 mg once a day, or placebo, 1 tablet once a day) the following parameters were measured: systolic and diastolic blood pressure (BP) and heart rate (HR) at rest by an automatic recorder; BP, HR, and cardiac workload (systolic BP X HR) during exercise testing on a bicycle; left ventricular mass (LVMe according to the method of Devereux) and cross-sectional area (CSA), and main parameters of systolic function (end diastolic volume, end systolic volume [ESV], and ejection fraction [EF]) by M mode echocardiography. There was a significant decrease in BP at rest (163/108 vs. 144/92 mm Hg; P less than 0.001) and during exercise in subjects receiving nitrendipine, while placebo did not modify these parameters. LVMe (from 195 to 188 gm; P less than 0.01) and CSA (from 20.2 to 19.8 cm2; P less than 0.05) were reduced by nitrendipine, which also improved cardiac performance (ESV fell from 44 to 38 ml [P less than 0.001] and EF fell from 62% to 66% [P less than 0.01]). No effect was observed in the placebo group. Our results indicate that nitrendipine is a powerful antihypertensive agent that also improves cardiac performance and slightly but significantly reduces left ventricular mass.

Mechanism of increased plasma urea after diuretic therapy in uraemic patients.

Abstract: To clarify why diuretic therapy raises plasma urea in patients with chronic renal failure, three groups of uraemic subjects were treated with frusemide for 6 days. In group 1 (n = 9), frusemide significantly decreased body weight and increased average plasma urea from 18.7 mmol/l to 28.8 mmol/l (P less than 0.001). this rise in plasma urea was secondary to reduced urea excretion, which occurred in spite of an increase in urea filtration. In group 2 (n = 7), frusemide was associated with salt replacement, in order to prevent salt depletion; in these patients neither reduction in urea excretion nor increase in plasma urea occurred. In group 3 (n = 10), the marked diuretic-induced fall in urea clearance was found to be independent of enhanced proximal tubular reabsorption (measured in water diuresis). These results show that the rise in plasma urea is due to increased tubular reabsorption of urea, presumably in the distal part of the nephron, secondary to extracellular fluid (ECF) volume depletion.

Activation of major histocompatibility complex class I mRNA containing an Alu-like repeat in polyoma virus-transformed rat cells.

Abstract: Activation of major histocompatibility complex class I mRNA containing an Alu-like repeat in polyoma virus-transformed rat cells