Showing papers by "University of Udine published in 1996"

Catalytic Properties of Ceria and CeO2-Containing Materials

Abstract: Over the past several years, cerium oxide and CeO2-containing materials have come under intense scrutiny as catalysts and as structural and electronic promoters of heterogeneous catalytic reactions. Recent developments regarding the characterization of ceria and CeO2-containing catalysts are critically reviewed with a special focus towards catalyst interaction with small molecules such as hydrogen, carbon monoxide, oxygen, and nitric oxide. Relevant catalytic and technological applications such as the use of ceria in automotive exhaust emission control and in the formulation of SO x reduction catalysts is described. A survey of the use of CeO2-containing materials as oxidation and reduction catalysts is also presented.

Primary motor and sensory cortex activation during motor performance and motor imagery: a functional magnetic resonance imaging study

Abstract: The intensity and spatial distribution of functional activation in the left precentral and postcentral gyri during actual motor performance (MP) and mental representation [motor imagery (MI)] of self-paced finger-to-thumb opposition movements of the dominant hand were investigated in fourteen right-handed volunteers by functional magnetic resonance imaging (fMRI) techniques. Significant increases in mean normalized fMRI signal intensities over values obtained during the control (visual imagery) tasks were found in a region including the anterior bank and crown of the central sulcus, the presumed site of the primary motor cortex, during both MP (mean percentage increase, 2.1%) and MI (0.8%). In the anterior portion of the precentral gyrus and the postcentral gyrus, mean functional activity levels were also increased during both conditions (MP, 1.7 and 1.2%; MI, 0.6 and 0.4%, respectively). To locate activated foci during MI, MP, or both conditions, the time course of the signal intensities of pixels lying in the precentral or postcentral gyrus was plotted against single-step or double-step waveforms, where the steps of the waveform corresponded to different tasks. Pixels significantly (r > 0.7) activated during both MP and MI were identified in each region in the majority of subjects; percentage increases in signal intensity during MI were on average 30% as great as increases during MP. The pixels activated during both MP and MI appear to represent a large fraction of the whole population activated during MP. These results support the hypothesis that MI and MP involve overlapping neural networks in perirolandic cortical areas.

A set of primers for the amplification of 20 chloroplast microsatellites in Pinaceae

Abstract: The forest tree speaes generally display very high level of genetic diversity (Miiller-Starck et al. 1992) and therefore an accurate analysis of the entity and distribution of their genetic resources requires the screening of many popuiations and many individuals within populations. Hence the choice of appropriate genetic markers assumes great importance in order to reduce costs and to save time. In particular genetic markers should be highly polymorphic and inherited in a Mendelian codominant manner. Microsatellites, or simple sequence repeats (SSR), that are tandem repeats of six base pairs or less (Litt Q Luty 1989; Weber Q May 1989), have these characteristics and therefore Seem to be suitable genetic markers for population genetic studies aIso in forest tree species. The length variation of the tandem repeats can easily be scored following amplification of the SSR-containing fragments by the polymerase chain reaction using unique flanking primers. In plants the possibility to screen highly polymorphic microsatellite regions also in the chloroplast genome, which shows lower mutation rates than the nuclear genome and is usually uniparentally inherited, might increase the knowledge about the biology of these organisms. In particular chloroplast microsatellites may be very useful for studying cytoplasmic diversity, cytonuclear interactions and monitoring gene flow. Powell ef al. (1995a,b) recently demonstrated the utility of the analysis of the length variation of chloroplast microsatellites. In particular they analysed (Powell et d. 1995b) a mononudeotide microsatellite located in the intergenic region between the trnK and psbA genes for assaying genetic variation in pine species. It was shown that the primers worked in aU the species tested and that the amplified fragment showed high levels of polymorphism due to size variations between and within species. Sequencing of the fragments confirmed that the size dif-

High glucose induces antioxidant enzymes in human endothelial cells in culture. Evidence linking hyperglycemia and oxidative stress

Abstract: It has been suggested that oxidative stress may play an important role in the pathogenesis of diabetic complications. Hyperglycemia may cause increased production of free radicals, and evidence supports a prominent role for these reactive molecules as mediators of endothelial cell dysfunction in diabetes. It has been demonstrated that active oxygen species induce antioxidant enzyme expression in some tissues, and this phenomenon is considered proof of an existing oxygen-dependent toxicity. In this study, human endothelial cells from umbilical vein, immortalized human endothelial cells, and immortalized human endothelial cells transfected to express high glutathione peroxidase levels were grown in normal and high-glucose conditions. High glucose delayed replication after 7 and 14 days of culture of human endothelial cells, both from umbilical vein and immortalized, while transfected cells were not affected. The activity and the mRNA expression of the antioxidant enzymes CuZn-superoxide-dismutase, Mn-superoxide-dismutase, catalase, and glutathione peroxidase were evaluated after 2, 7, and 14 days of culture. High glucose at days 7 and 14 induced an overexpression of CuZn-superoxide-dismutase, catalase, and glutathione peroxidase in both human endothelial cells from umbilical vein and immortalized human endothelial cells, while in transfected cells it did not. This study demonstrates that high glucose induces an increase in antioxidant enzyme levels in human endothelial cells, suggesting that elevated glucose levels may produce an oxidative stress in the cells.

Alzheimer's Disease Associated with Mutations in Presenilin 2 is Rare and Variably Penetrant

Abstract: Missense mutations in the presenilin 2 (PS-2) gene on chromosome 1 were sought by direct nucleotide sequence analysis of the open reading frame of 60 pedigrees with familial Alzheimer's disease (FAD) In the majority of these pedigrees, PS-1 and beta-amyloid precursor protein (beta APP) gene mutations had been excluded While no additional PS-2 pathogenic mutations were detected, four silent nucleotide substitutions and alternative splicing of nucleotides 1338-1340 (Glu325) were observed Analysis of additional members of a pedigree known to segregate a Met239Val mutation in PS-2 revealed that the age of onset of symptoms is highly variable (range 45-88 years) This variability is not attributable to differences in ApoE genotypes These results suggest (i) that, in contrast to mutations in PS-1, mutations in PS-2 are a relatively rare cause of FAD; (ii) that other genetic or environmental factor modify the AD phenotype associated with PS-2 mutations; and (iii) that still other FAD susceptibility genes remain to be identified

Performance of the DELPHI detector

Abstract: DELPHI (DEtector with Lepton, Photon and Hadron Identification) is a detector for e^+e^- physics, designed to provide high granularity over a 4\pi solid angle, allowing an effective particle identification. It has been operating at the LEP (Large Electron-Positron) collider at CERN since 1989. This article reviews its performance.

Preemptive Analgesia: Intraperitoneal Local Anesthetic in Laparoscopic Cholecystectomy A Randomized, Double-blind, Placebo-controlled Study

Abstract: BackgroundA controversy exists over the effectiveness and clinical value of preemptive analgesia. Additional studies are needed to define the optimum intensity, duration, and timing of analgesia relative to incision and surgery.MethodsOne hundred twenty patients undergoing laparoscopic cholecystecto

Tuning and test of fragmentation models based on identified particles and precision event shape data

Abstract: Event shape and charged particle inclusive distributions are measured using 750000 decays of the Z to hadrons from the DELPHI detector at LEP. These precise data allow a decisive confrontation with models of the hadronization process. Improved tunings of the JETSET, ARIADNE and HERWIG parton shower models and the JETSET matrix element model are obtained by fitting the models to these DELPHI data as well as to identified particle distributions from all LEP experiments. The description of the data distributions by the models is critically reviewed with special importance attributed to identified particles.

Investigation of the use of honey bees and honey bee products to assess heavy metals contamination.

Abstract: Experiment was carried out using 12 colonies of honey bees bred in hives located near an extraurban crossroad. We analyzed the Pb, Cd and Zn deposited on the bee's surfaces and the heavy metal accumulation in the foragers, dead bees, honey products and some environmental markers during nine weeks of the experiment. Results showed a large amount of Zn and Cd on the bee's surface as a consequence of atmospheric fallout, whereas Pb seems to be either water-extractable and/or likely accumulated in the body of the insect. Dead bees expelled from the hives displayed a progressive accumulation of all heavy metals during the experimental period. Royal jelly and honey contained large amounts of heavy metals. In particular, we found a linear relationship between Cd in the honey and that found in flowers of Trifolium pratense L. Results obtained suggested that honey bee products and the examined environmental markers may be considered useful parameters to assess the presence of environmental contaminants, whereas the measurements of heavy metals in the dead bees may be considered a suitable tool also to verify a possible dynamics of accumulation of pollutants.

{0, 1 2 }-Chva´tal-Gomory cuts

Abstract: Given the integer polyhedronP t := conv{x ∈ℤ n :Ax⩽b}, whereA ∈ℤ m × n andb ∈ℤ m , aChvatal-Gomory (CG)cut is a valid inequality forP 1 of the type λτAx⩽⌊λτb⌋ for some λ∈ℝ + such that λτA∈ℤ n . In this paper we study {0, 1/2}-CG cuts, arising for λ∈{0, 1/2} m . We show that the associated separation problem, {0, 1/2}-SEP, is equivalent to finding a minimum-weight member of a binary clutter. This implies that {0, 1/2}-SEP is NP-complete in the general case, but polynomially solvable whenA is related to the edge-path incidence matrix of a tree. We show that {0, 1/2}-SEP can be solved in polynomial time for a convenient relaxation of the systemAx<-b. This leads to an efficient separation algorithm for a subclass of {0, 1/2}-CG cuts, which often contains wide families of strong inequalities forP 1. Applications to the clique partitioning, asymmetric traveling salesman, plant location, acyclic subgraph and linear ordering polytopes are briefly discussed.

Genepool Variation in Genus Glycine Subgenus Soja Revealed by Polymorphic Nuclear and Chloroplast Microsatellites

Abstract: A combination of nuclear and chloroplast simple sequence repeats (SSRs) have been used to investigate the levels and pattern of variability detected in Glycine max and G. soja genotypes. Based on the analysis of 700 soybean genotypes with 115 restriction fragment length polymorphism (RFLP) probes, 12 accessions were identified that represent 92% of the allelic variability detected in this genepool. These 12 core genotypes together with a sample of G. max and G. soja accessions were evaluated with 11 nuclear SSRs that detected 129 alleles. Compared with the other G. max and G. soja genotypes sampled, the core genotypes represent 40% of the allelic variability detected with SSRs. Despite the multi-allelic nature of soybean SSRs, dendrograms representing phenetic relationships between accessions clustered according to their subspecies origin. In addition to biparentally inherited nuclear SSRs, two uniparentally (maternally) transmitted chloroplast SSRs were also studied. A total of seven haplotypes were identified, and diversity indices of 0.405 +/- 0.088 and 0.159 +/- 0.071 were obtained for the two chloroplast SSRs. The availability of polymorphic SSR loci in the chloroplast genome provides new opportunities to investigate cytonuclear interactions in plants.

Risk factors for vascular disease and arteriovenous fistula dysfunction in hemodialysis patients.

Abstract: Vascular access dysfunction is an important cause of morbidity for dialysis patients and a major contributor to hemodialysis cost. Thrombosis is a leading cause of vascular access failure, and usually results from stenotic lesions in the venous outflow system. This study was designed to explore the impact of serum levels of various risk factors for thrombosis and accelerated fibrointimal hyperplasia on progressive stenosis, and the subsequent thrombosis of hemodialysis fistula. A cross-sectional and 2-yr prospective pilot study was performed in 30 nondiabetic hemodialysis patients with primary arteriovenous fistula. Venous dialysis pressure, urea recirculation, color Doppler sonography, and angiography were used to monitor vascular access patency. Eleven patients (37%) developed a progressive stenosis in the venous circuit, which was complicated by thrombosis in three patients. Compared with the patients without fistula dysfunction, these patients had higher serum levels of monocyte chemoattractant protein-1 and interleukin-6, two cytokines that regulate the proliferation of vascular smooth muscle cells, which is the key mechanism in the pathogenesis of fistula stenosis. In addition, they had hyperinsulinemia, hyperlipidemia, and increased plasma levels of two hemostasis-derived risk factors for thrombosis: plasminogen activator inhibitor type 1 and factor VII. Monocyte chemoattractant protein-1, interleukin-6, plasminogen activator inhibitor type 1, factor VII, triglycerides, and the ratios for cholesterol/HDL-cholesterol, apolipoprotein (apo) A-I/ apo C-III, apo A-I/apo B, and glucose/insulin were independent predictors of fistula dysfunction. This study demonstrates the influece of cytokines, hemostasis-derived vascular risk factor, hyperinsullnemia, and abnormallties of lipids and apolipoproteins on primary fistula survival. The assessment of these factors might be useful for the identification of the patients at risk of fistula stenosis and thrombosis.

Post-meal coagulation activation in diabetes mellitus: the effect of acarbose

Abstract: It has been previously demonstrated that hyperglycaemia activates haemostasis; diabetes mellitus is considered a thrombosis-prone state. Acarbose, by inhibiting dietary carbohydrate absorption, reduces post-meal hyperglycaemia. In this study we evaluated the effect of post-meal hyperglycaemia on two markers of coagulation activation: prothrombin fragments 1 + 2 and D-dimer. Seventeen non-insulin-dependent diabetic patients maintained on diet therapy alone were randomly assigned to receive — with a cross-over study design — acarbose (100 mg orally) or placebo before a standard meal. Blood samples for measurement of plasma glucose, insulin, prothrombin fragments 1 + 2 and D-dimer were drawn at 0, 60, 120 and 240 min. After both placebo and acarbose, hyperglycaemia and hyperinsulinaemia which followed a standard meal were accompanied by a significant increase of plasma concentration of prothrombin fragments 1 + 2 and D-dimer in comparison to their baseline values. Acarbose administration significantly reduced the rise of glucose, insulin, prothrombin fragments 1 + 2 and D-dimer from 0 to 240 min in comparison to placebo. We conclude that post-meal hyperglycaemia, at the level reached by many diabetic patients on diet therapy alone, induces a coagulation activation. Acarbose, by decreasing post-meal hyperglycaemia, may be useful in reducing meal-induced activation of haemostasis in diabetic patients.

Evaluating user interfaces to information retrieval systems: a case study on user support

Abstract: Designing good user interfaces to information retrieval systems is a complex activity. The design space is large and evaluation methodologies that go beyond the classical precision and recall figures are not well established. In this paper we present an evaluation of an intelligent interface that covers also the user-system interaction and measures user's satisfaction. More specifically, we describe an experiment that evaluates: (i) the added value of the semiautomatic query reformulation implemented in a prototype system; (ii) the importance of technical, terminological, and strategic supports and (iii) the best way to provide them. The interpretation of results leads to guidelines for the design of user interfaces to information retrieval systems and to some observations on the evaluation issue.

The antioxidant capacity of complex mixtures by kinetic analysis of crocin bleaching inhibition

Abstract: The capability of a compound or of a mixture of compounds to quench peroxyl radicals was measured by analyzing the kinetics of the competition of a parallel reaction where peroxyl radicals bleach the carotenoid crocin. This kinetic approach, originally described for the analysis of antioxidants reacting with hydroxyl radicals in water, was modified by both decreasing the polarity of the solvent, thus allowing the analysis of lipophilic compounds, and by substituting a source of peroxyl radicals for the hydroxyl radical generating system. Single compounds as well as complex mixtures were analyzed by kinetic data processing. Overall antioxidant capacity, relative to that of α-tocopherol or of its soluble analog Trolox C, was calculated. As examples of the use of this test, the antioxidant capacities of a crude rosemary extract, Maillard reaction products, and virgin olive oils were measured.

Single-Spin Asymmetries in Inclusive Charged Pion Production by Transversely Polarized Antiprotons.

Abstract: The analyzing power ${A}_{N}$ in inclusive ${\ensuremath{\pi}}^{\ensuremath{-}}$ and ${\ensuremath{\pi}}^{+}$ production has been measured with a 200 GeV/c transversely polarized antiproton beam over a wide ${x}_{F}$ range $(0.2\ensuremath{\le}{x}_{F}\ensuremath{\le}0.9)$ and at moderate ${p}_{T}$ $(0.2\ensuremath{\le}{p}_{T}\ensuremath{\le}1.5\mathrm{GeV}/\mathrm{c})$. The asymmetry ${A}_{N}$ increases with increasing ${x}_{F}$ from zero to large positive values for ${\ensuremath{\pi}}^{\ensuremath{-}}$'s, and decreases from zero to large negative values for ${\ensuremath{\pi}}^{+}$'s. A threshold for the onset of the asymmetry is observed about ${p}_{T}\ensuremath{\sim}0.5\mathrm{GeV}/\mathrm{c}$, below which ${A}_{N}$ is essentially zero and above which ${A}_{N}$ increases (decreases) with ${p}_{T}$ for ${\ensuremath{\pi}}^{\ensuremath{-}}$'s ( ${\ensuremath{\pi}}^{+}$'s) in the covered ${p}_{T}$ range.

Lean organization, management by process and performance measurement

Abstract: Shows how the pursuit of excellence and the organizational change required by lean production leads to a management‐by‐process organization, and that management by process influences the performance measurement system (PMS). Uses Zanussi‐Electrolux ‐ the biggest European producer of domestic appliances ‐ as a case study example. Provides a detailed analysis of the organizational change and its effects on performance measurement.

A molecular code dictates sequence-specific DNA recognition by homeodomains.

Abstract: Most homeodomains bind to DNA sequences containing the motif 5'-TAAT-3'. The homeodomain of thyroid transcription factor 1 (TTF-1HD) binds to sequences containing a 5'-CAAG-3' core motif, delineating a new mechanism for differential DNA recognition by homeodomains. We investigated the molecular basis of the DNA binding specificity of TTF-1HD by both structural and functional approaches. As already suggested by the three-dimensional structure of TTF-1HD, the DNA binding specificities of the TTF-1, Antennapedia and Engrailed homeodomains, either wild-type or mutants, indicated that the amino acid residue in position 54 is involved in the recognition of the nucleotide at the 3' end of the core motif 5'-NAAN-3'. The nucleotide at the 5' position of this core sequence is recognized by the amino acids located in position 6, 7 and 8 of the TTF-1 and Antennapedia homeodomains. These data, together with previous suggestions on the role of amino acids in position 50, indicate that the DNA binding specificity of homeodomains can be determined by a combinatorial molecular code. We also show that some specific combinations of the key amino acid residues involved in DNA recognition do not follow a simple, additive rule.

Efficient temporal reasoning in the cached event calculus

Abstract: This article deals with the problem of providing Kowaiski and Sergot's event calculus, extended with context dependency, with an efficient implementation in a logic programming framework. Despite a widespread recognition that a positive solution to efficiency issues is necessary to guarantee the computational feasibility of existing approaches to temporal reasoning, the problem of analyzing the complexity of temporal reasoning programs has been largely overlooked. This article provides a mathematical analysis of the efficiency of query and update processing in the event calculus and defines a cached version of the calculus that (i) moves computational complexity from query to update processing and (ii) features an absolute improvement of performance, because query processing in the event calculus costs much more than update processing in the proposed cached version.

Scheduling Jobs on Several Machines with the Job Splitting Property

Abstract: This scheduling model is derived from the real problem of scheduling looms in a textile industry. Jobs may be independently split over several specified machines, and preemption is allowed. Deadlines are specified for each job, and jobs are assumed to be available. It is shown that minimizing maximum weighted tardiness can be done in polynomial time. The case of uniform machines as in the considered application can be modeled as a network flow, and minimization of maximum tardiness can be done in strongly polynomial time. The case of unrelated machines can be solved either by generalized flow techniques or by Linear Programming. Attention is also focused on the problem of finding so-called Unordered Lexico Optima, in order to schedule nonbinding jobs as early as possible.

Increased circulating intercellular adhesion molecule-1 levels in type ii diabetic patients: the possible role of metabolic control and oxidative stress

Abstract: Blood levels of the circulating form of the integrin intercellular adhesion molecule-1 (ICAM-1), malondialdehyde (MDA), and hemoglobin A1c (HbA1c) were studied at baseline and 3 months after improved metabolic control in 25 type II diabetic patients without signs of macroangiopathy, and were compared with those in 15 matched healthy normal controls. Circulating ICAM-1 and MDA levels were increased in diabetic patients, both at baseline and 3 months later. However, with improving metabolic control HbA1c, circulating ICAM-1, and MDA significantly decreased. A significant correlation between circulating ICAM-1, HbA1c, and MDA was found in diabetic patients at each time. Multiple regression analysis considering circulating ICAM-1 as the dependent variable and HbA1c and MDA as independent variables, showed a significant correlation between the three variable at each time. Similar correlations were found in control subjects. These data show increased levels of circulating ICAM-1 in type II diabetic patients, independent of the presence of macroangiopathy. Moreover, these results suggest that oxidative stress and metabolic control might participate in determining increased circulating ICAM-1 levels in both type II diabetic patients and normal subjects.