Showing papers by "University of Udine published in 1991"
TL;DR: A meta-level definition of abduction in l d terms of deduction, similar to various definitions proposed in the literature, and an object-leve efinition in which abductive conclusions are expressed as a logical consequence of the obser.
Abstract: n a The aim of this paper is at analyzing from various points of view the relationships betwee bduction and deduction. In particular, we consider a meta-level definition of abduction in l d terms of deduction, similar to various definitions proposed in the literature, and an object-leve efinition in which abductive conclusions are expressed as a logical consequence of the obser. T vations and of a simple transformation of the domain theory based on predicate completion he equivalence between the two definitions is proved for domain theories of considerable s expressive power. The object-level characterization we propose uses very simple forms of rea oning and the equivalence result allows us to make explicit some of the assumptions underly-
279 citations
Rice University1, University of Iowa2, Fermilab3, Kyoto University4, Argonne National Laboratory5, Hiroshima University6, Northeastern State University7, Northwestern University8, University of Udine9, University of Trieste10, University of Messina11, Kyoto Sangyo University12, Okayama University13, Los Alamos National Laboratory14, Osaka City University15
TL;DR: In this article, the analyzing power in inclusive charged pion production has been measured using the 200 GeV Fermilab polarized proton beam, and it was shown that at large x(F) the transverse spin of the proton is correlated with that of its quark constituents.
275 citations
TL;DR: It is demonstrated that vitamin E administration may reduce protein glycosylation in diabetic subjects independently of changes in plasma glucose, an effect that may be due to the inhibition of labile gly cosylation, the first step of the Maillard reaction.
Abstract: Objective This study evaluated the possibility of inhibiting protein glycosylation in vivo with vitamin E. Research Design and Methods Two groups of 10 insulin-requiring diabetic patients, matched for duration of disease and metabolic control, received daily vitamin E supplementation of 1200 and 600 mg, respectively, for 2 mo. A third group of 10 diabetic patients, matched for duration of disease and metabolic control, served as the control group and received placebo. Fasting plasma glucose, mean daily plasma glucose, fasting labile HbA 1 , and glycosylated proteins were measured in the basal state and after 1 and 2 mo of treatment. In addition, hyperglycemic clamp studies were performed in basal state and after 1 mo of vitamin E administration in all patients. Results Glycemic indices did not show any significant changes during the study, whereas fasting labile HbA, and glycosylated proteins decreased significantly after 1 and 2 mo in patients on vitamin E administration. Stable HbA 1 decreased after 2 mo. Mean glycemic incremental area in the hyperglycemic clamp procedure was similar before and after treatment, whereas a significant reduction in mean labile HbA 1 incremental area was found after vitamin E supplementation. A significant difference was also found in both fasting and incremental labile HbA 1 levels, stable HbA 1 , and glycosylated proteins between the two groups of diabetic patients on the two doses of vitamin E; the diabetic patients who received the higher dose of vitamin E showed the greater reduction. No significant changes in these parameters were observed in diabetic patients on placebo administration. Conclusions These results demonstrate that vitamin E administration may reduce protein glycosylation in diabetic subjects independently of changes in plasma glucose, an effect that may be due to the inhibition of labile glycosylation, the first step of the Maillard reaction. Long-term studies will help establish the usefulness of vitamin E administration for the prevention of diabetic complications.
257 citations
Rice University1, University of Iowa2, Fermilab3, Kyoto University4, Argonne National Laboratory5, Hiroshima University6, Northeastern State University7, Northwestern University8, University of Occupational and Environmental Health Japan9, University of Udine10, University of Trieste11, University of Messina12, Kyoto Sangyo University13, Okayama University14, Los Alamos National Laboratory15, Osaka City University16
TL;DR: In this article, the single-spin asymmetry of antiprotons on protons was measured at Fermilab over a wide range of x{sub F, and it was observed that A{sub N}(anti pp) has the same sign, a similar x-sub F dependence, and about half the magnitude as A {pi}{sup 0} production by protons.
183 citations
TL;DR: In this paper, the direct room-temperature synthesis of most metal carbides by milling metal-carbon powders (size some tens of micrometers) mixtures is described.
Abstract: The direct room-temperature synthesis (mechanochemical synthesis or mechanosynthesis—MS) of most metal carbides by milling metal—carbon powders (size some tens of micrometers) mixtures is described. The particle size of the carbides obtained is of the order of 20 nm. Stable, metastable, mixed, and new carbides can be formed. Moreover, metal—carbon alloys can be obtained, such as in the Fe—C system. The synthesized compounds have been characterized by X-ray diffraction and Mossbauer spectroscopy for iron-containing systems. Carbides of the following elements were obtained: Ti, V, Cr, Mn, Fe, Co, Ni, Zr, Nb, Mo, Hf, Ta, W, Re, Al and Si.
141 citations
01 Jan 1991
TL;DR: The primary structure of phospholipid hydroperoxide glutathione peroxidase (PHGPx) was partially elucidated by sequencing peptides obtained by cyanogen bromide cleavage and tryptic digestion and by isolating and sequencing corresponding cDNA fragments covering about 75% of the total sequence.
Abstract: The primary structure of phospholipid hydroperoxide glutathione peroxidase (PHGPx) was partially elucidated by sequencing peptides obtained by cyanogen bromide cleavage and tryptic digestion and by isolating and sequencing corresponding cDNA fragments covering about 75% of the total sequence. Based on these data PHGPx can be rated as a selenoprotein homologous, but poorly related to classical glutathione peroxidase (GPx). Peptide loops constituting the active site in GPx are, however, strongly conserved in PHGPx. This suggests that the mechanism of action involving an oxidation/reduction cycle of a selenocysteine residue is essentially identical in PHGPx and GPx.
139 citations
TL;DR: In this article, the effect of glucose, fructose and sucrose aqueous solutions on polyphenol oxidase (PPO) and peroxidase (POD) activity was studied.
Abstract: The effect of glucose, fructose and sucrose aqueous solutions on polyphenol oxidase (PPO) and peroxidase (POD) activity was studied. Solutions with high concentrations of sugars showed a slight inhibiting effect on PPO while an activation was observed for POD. Glucose solutions, tested after sufficient heat treatments, showed an inhibiting action only on PPO activity. Maillard reaction products, obtained by heating a glucose/glycine solution, caused an unexpectedly strong inhibiting effect on both enzymes. The inhibition became more evident with increasing heating times of the glucose/glycine solution, reducing the activity of PPO and POD nearly to zero. Thus, the Maillard reaction products, already known for their antioxidant properties, were also shown to have a strong inhibiting effect on enzymatic browning.
106 citations
TL;DR: In this paper, the presence of a surface peroxidase at the plasma membrane of the plant cells has been investigated, which is able to catalyze, through a chain of reactions involving the superoxide anion, the oxidation of NADH to generate hydrogen peroxide.
Abstract: In addition to well-known cell wall peroxidases, there is now evidence for the presence of this enzyme at the plasma membrane of the plant cells (surface peroxidase). Both are able to catalyze, through a chain of reactions involving the superoxide anion, the oxidation of NADH to generate hydrogen peroxide. The latter is oxidized by other wall-bound peroxidases to convert cinnamoyl alcohols into radical forms, which, then polymerize to generate lignin. However, there are other enzymes at the surface of plasma membranes capable of generating hydrogen peroxide (cell wall polyamine oxidase), superoxide anion (plasma membrane Turbo reductase), or both (plasma membrane flavoprotein?). These enzymes utilize NAD(P)H as a substrate. The Turbo reductase and the flavoprotein catalyze the univalent reduction of Fe3+ and then of O2 to produce Fe2+ and
$$O_2^{\bar \cdot } $$
, respectively. The superoxide anion, in the acidic environment of the cell wall, may then dismutate to H2O2. These superoxide anion- and hydrogen peroxide-generating systems are discussed in relation to their possible involvement in physiological and pathological processes in the apoplast of plant cells.
102 citations
TL;DR: Two monoclonal antibodies, MRK16 and C219, both directed at the 170 kDa P‐glycoprotein multidrug resistance agent, were applied to frozen sections or cytospin preparations from normal human tissues and 60 non‐Hodgkin's malignant lymphomas and a close relationship was shown between the presence of P1 70 positive elements and the clinical course of the disease.
Abstract: Two monoclonal antibodies, MRK16 and C219, both directed at the 170 kDa P-glycoprotein multidrug resistance agent, were applied to frozen sections or cytospin preparations from normal human tissues and 60 non-Hodgkin's malignant lymphomas. Adrenal gland, kidney, liver and pancreas were always stained by the reagents, albeit with slightly different patterns. Brain capillaries as well as macrophages and some elements of the bone marrow, peripheral blood, ovarian stroma and colonic, gastric and jejunal mucosa were positive in all examined preparations. There were differences in the staining patterns with the two antibodies. Among the 60 non-Hodgkin's lymphomas, 25 contained a number of positive cells, which ranged from 2% to 100%. No correlation was seen between the expression of P170 and histological type, stage, clinical symptoms or growth fraction. A close relationship was shown between the presence of P170 positive elements and the clinical course of the disease (P less than 0.001).
100 citations
TL;DR: The results indicated that sea bass are able to utilise successfully large amounts of alternative protein sources such as maize gluten, providing that adequate levels of lysine and other essential amino acids are present in the diet.
87 citations
TL;DR: In this paper, the linear state feedback synthesis problem for uncertain linear systems with state and control constraints is considered and the main goal is to find a linear control law assuring that both state and input constraints are fulfilled at each time.
Abstract: The linear state feedback synthesis problem for uncertain linear systems with state and control constraints is considered. We assume that the uncertainties are present in both the state and input matrices and they are bounded. The main goal is to find a linear control law assuring that both state and input constraints are fulfilled at each time. The problem is solved by confining the state within a compact and convex positively invariant set contained in the allowable state region.
TL;DR: Two different members of the phosphoenolpyruvate carboxylase(PEPC)-encoding multigene family have been isolated from a Sorghum vulgare lambda EMBL4 genomic library and it is indicated that lambda CP21 and lambda CP46 encode the C3- and C4-type leaf PEPC isoforms, respectively.
TL;DR: In this article, a simple and efficient model for first-order simulation of the writing of n-channel erasable programmable ROM (EPROM) cells is presented, which allows the current injected into the gate insulator of the cell transistor to be calculated, accounting (at first order) both for the nonMaxwellian form of the electron energy distribution and for a nonlocal nature of carrier heating.
Abstract: A simple and efficient model for first-order simulation of the writing of n-channel erasable programmable ROM (EPROM) cells is presented. It allows the current injected into the gate insulator of the cell transistor to be calculated, accounting (at first order) both for the nonMaxwellian form of the electron energy distribution and for the nonlocal nature of carrier heating. The model is implemented as a postprocessor of a two-dimensional device simulator, and it is validated by means of a comparison with experimental data obtained with devices with effective channel lengths ranging from 1.4 to 0.5 mu m. >
30 Dec 1991-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, the solid state reduction of haematite (α-Fe2O3) to mainly nanocrystalline wustite by room temperature dry ball milling of hahematite and carbon, in an inert atmosphere, is described.
Abstract: The solid state reduction of haematite (α-Fe2O3) to mainly nanocrystalline wustite by room temperature dry ball milling of haematite and carbon, in an inert atmosphere, is described. In addition to wustite, a smaller amount of nanocrystalline magnetite is also formed, possibly by a disproportionation reaction of wustite. The reaction is completed in about 70 h in a Spex vibratory ball mill. Haematite alone is converted by dry milling for 70 h into nanocrystalline magnetite with an average crystallite size of 10 nm as shown by X-ray diffraction and Mossbauer spectroscopy.
TL;DR: The activity of glutathione-dependent reduction of dehydroascorbate, although measurable, appeared negligible and the one-electron reduction of ascorbyl radical resulted fast enough to slow down the consumption of the antioxidant vitamin.
TL;DR: The generation of hybrid genes between two truncated cryIA genes were cloned in a plasmid vector in such way as to have only the hypervariable region in common and allowed the production of eight different hybrid proteins.
TL;DR: Roots, stems and leaves of Phaseolus vulgaris L. Rubino PF1H grown in Hoagland's solution supplemented with 1, 2 and 2.5 mM Cd 2+ showed a significant decrease in fresh weight and per cent dry matter in roots, whereas stems were slightly affected and leaves not at all, compared with control plants grown in a nutrient solution containing equivalent amounts of NO 3 − added as KNO 3.
TL;DR: In this article, the authors present experimental evidence of the Class I "ductile" vs the Class II "brittle" response observed on the global level for rock and rock-like materials.
TL;DR: Maillard reaction volatile compounds (MRV), prepared by heating a glucose-glycine solution, were tested as antioxidants in soybean oil (SBO) thermoxidation as mentioned in this paper.
Abstract: Maillard reaction volatile compounds (MRV), prepared by heating a glucose-glycine solution, were tested as antioxidants in soybean oil (SBO) thermoxidation. The volatiles were transferred into the oil by stripping with a stream of Nitrogen and substituting the atmosphere above the oil with air containing MRV. Standard accelerated oxidation was performed by heating the SBO. Peroxide value measurement and headspace gas Chromatographic analysis were carried out on all the samples. The MRV antioxidant activity was evaluated by determining the effect of the induction period and the kinetic rate constant of peroxide and oxidation volatiles formation. The MRV showed a significant antioxidant activity. The effectiveness was variable depending on MRV transfer method to the oil, and the Maillard reaction extent was related to the browning level of glucose/glycine solution. It was found that the maximum effect of MRV prolonged about three times the induction period and reduced the kinetic rate constant by half in relation to the control sample. MRV affects oxidative stability of soybean oil by lengthening the induction period as well as by decreasing the rate of oxidation at the propagation state and reducing the formation of hexanal.
10 Jul 1991-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this paper, an improved method based on the measurement of the attenuation of a current due to an electron cloud, photoproduced by a laser pulse impinging on a metallic cathode and moving in a small drift chamber filled with the purified liquid Ar (LAr), was proposed.
Abstract: As part of the development program for the ICARUS experiment, which consists of a very large time projection chamber (TPC) filled with ultra-pure liquid Ar (LAr), we have carried out tests with different purifier systems, in order to evaluate the performance of the various parts and to improve the purification techniques developed so far.
Electron lifetime τ in LAr has been determined with an improved method based on the measurement of the attenuation of a current due to an electron cloud, photoproduced by a laser pulse impinging on a metallic cathode and moving in a small drift chamber filled with the purified LAr. Results of the above-mentioned tests are reported. During these tests, we observed repeatedly and reproducibly an increase of τ that took place over a period of 10 to 20 h after liquefaction. Several tests performed in an attempt to elucidate this effect, suggest that the increase in τ is due to adsorption of electron-attaching impurities on the walls of the stainless steel container, a process governed by thermal diffusion. The electron lifetime monitoring system reported here was used to measure the electric field dependence of τ in purified LAr doped with O2 and CO2, for fields 100 V/cm < E < 800 V/cm: The results for O2 are consistent with published data.
TL;DR: The results indicated the decomposition of H2O2 by redox-active iron-protein adducts as responsible for the enzyme inactivation, probably through site-directed generation of more highly reactive oxygen species.
TL;DR: This work examines the distribution of heavy metals in two contaminated environments, a smelter-refinery and a mine area situated in S.W. Sardinia and target organs of sheep and lamb were considered for their heavy metals accumulation.
Abstract: It is widely known that anthropogenic activities strongly contributed to heavy metals contamination of the environment. For this reason, distribution of heavy metals in soils and plants around urban and industrial point sources have been the object of extensive studies. Lesser attention has been given to accumulation of heavy metals in animals bred in these polluted environments, and relatively few works are concerned with the accumulation of heavy metals through the food chain. The aim of this work is to examine the distribution of heavy metals in two contaminated environments, a smelter-refinery and a mine area situated in S.W. Sardinia. The first sampling area is located near one of the most important Pb and Zn smelting-refineries of Europe, and the second near abandoned and working mines. In this study, target organs of sheep and lamb were considered for their heavy metals accumulation. Samples of vegetation were collected throughout the vegetative period and analyzed for their Pb, Zn and Cd content. Winter forage and soil were also sampled.
TL;DR: The classical theory of continuous distributions of dislocations has traditionally focused on the Burgers' vectors and the dislocation density tensor as descriptions of defectiveness as mentioned in this paper, and it has been shown that there is an infinite number of tensor densities with similarly descriptive properties, and that the changes of state which preserve these densities turn out to represent slip in certain surfaces associated with crystal geometry.
Abstract: The classical theory of continuous distributions of dislocations has traditionally focused on the Burgers' vectors and the dislocation density tensor as descriptions of defectiveness We prove that, generally, there is an infinite number of tensor densities with similarly descriptive properties, and that there is a functional basis for this list which strictly includes the Burgers' vectors and dislocation density Moreover the changes of state which preserve these densities turn out to represent slip in certain surfaces associated with crystal geometry, so that the basic mechanism of plasticity emerges naturally from abstract ideas which neither anticipate nor involve the kinematics of particular types of crystal defects
TL;DR: This paper presents an architecture for diagnostic problem solving based on the use of a pathophysiological model in which both causal and temporal relations are explicitly represented and shows that in such an extended framework diagnostic problems can be solved correctly only by means of a strict co-operation between abductive and temporal reasoning.
TL;DR: In this paper, the multiplicity distributions of charged particles in restricted rapidity intervals in Z0 hadronic decays measured by the DELPHI detector are presented, revealing a shoulder structure, best visible for intervals of intermediate size.
Abstract: The multiplicity distributions of charged particles in restricted rapidity intervals inZ0 hadronic decays measured by the DELPHI detector are presented. The data reveal a shoulder structure, best visible for intervals of intermediate size, i.e. for rapidity limits around ±1.5. The whole set of distributions including the shoulder structure is reproduced by the Lund Parton Shower model. The structure is found to be due to important contributions from 3-and 4-jet events with a hard gluon jet. A different model, based on the concept of independently produced groups of particles, “clans”, fluctuating both in number per event and particle content per clan, has also been used to analyse the present data. The results show that for each interval of rapidity the average number of clans per event is approximately the same as at lower energies.
TL;DR: Two experiments confirmed the contention of this model that the relevant proximal contours for the judgment of partial transparency of the two overlapping transparent surfaces in a bistable pattern correspond to the part where these surfaces are superimposed.
Abstract: A model of achromatic transparency based on the idea that neural representations of transparency are activated by proximal contours is described. It is proposed that the weighted average of the magnitudes of the representations of transparency relative to a perceived continuous transparent surface corresponds to the judgment of the overall degree of transparency of the same surface. Tests of thiB weighted-average model were carried out with bistable patterns formed by two overlapping surfaces that appeared opaque where they were superimposed on the background and transparent where they were superimposed on each other (partial transparency). In agreement with predictions from the weighted-average model, the rated degrees of transparency of these two surfaces were noncomplementary and independent of background reflectance. Two experiments confirmed the contention of this model that the relevant proximal contours for the judgment of partial transparency of the two overlapping transparent surfaces in a bistable pattern correspond to the part where these surfaces are superimposed.
TL;DR: A close microanatomical relationship between serotonin-positive mast cells and nerve fibres positive for substance P, calcitonin gene related peptide, vasoactive intestinal polypeptide, and somatostatin has been observed in whole-mount preparations of rat mesentery by an immunofluorescent double-staining procedure.
Abstract: A close microanatomical relationship between serotonin-positive mast cells and nerve fibres positive for substance P, calcitonin gene related peptide, vasoactive intestinal polypeptide, and somatostatin has been observed in whole-mount preparations of rat mesentery by an immunofluorescent double-staining procedure. Peptidergic fibres have been shown either to run in close proximity or come in direct contact with mast cells. This supports earlier morphological and immunohistochemical results suggesting an innervation of mast cells and provides a structural foundation for a series of pharmacological studies which outline the influence of various neuropeptides on mast cell secretory activity.
TL;DR: The change of the enzyme activation kinetics by Mg 2+ , ATP, Na + and K + from simple saturation in FW to cooperativity in BW and other habitat-dependent variations including the pH alkaline shift in BW are hypothetically related to an adaptive significance to the different environmental salinity.
Abstract: 1. 1. The expected higher gill (Na + +K + )-ATPase activity in rainbow trout adapted to brackish water (BW) with respect to fresh water (FW) is accompanied by some changes in the enzyme kinetics while the enzyme sensitivity to ouabain is unaffected 2. 2. Maximal activation is attained under the optimal conditions of 4 mM ATP, 7.5 mM Mg 2+ , 50 mM Na + , 2.5 mM K + , pH 7.0 in FW, and 3 mM ATP, 10 mM Mg 2+ , 100 mM Na + , 10 mM K + , pH 7.5 in BW. 3. 3. The change of the enzyme activation kinetics by Mg 2+ , ATP, Na + and K + from simple saturation in FW to cooperativity in BW and other habitat-dependent variations including the pH alkaline shift in BW are hypothetically related to an adaptive significance to the different environmental salinity. 4. 4. Gill total lipids and phospholipids are 30% lower in BW than in FW while their ratio is constant; some differences in gill total lipid fatty acid composition between FW and BW do not significantly affect the unsaturation parameters.
TL;DR: It is concluded that at least two main growth reducing mechanisms exist of which the relative importance varies with time, reduced apparent assimilation rates and a reduced dry matter accumulation resulting from a decrease of water uptake.
Abstract: Potatoes were grown under a permanent rain shelter in mobile containers in soil with and without potato cyst nematodes (Globodera pallida). The plants were either subjected to an early drought stress period from planting until 43 days after planting, to a late drought stress period during tuber bulking or to a drought control. Leaf water potentials, stomatal diffusion resistances for water vapour, transpiration rates, dry matter accumulation and water use efficiencies of the plants were determined periodically. Both drought and nematodes decreased leaf water potential and increased stomatal resistance.