Showing papers by "University of Udine published in 1990"
TL;DR: In this paper, the authors show that triple-stranded polynucleotides can be formed by a duplex-to-triplex transition with an average change in enthalpy of −73(±5) kcal/mol of triplex.
150 citations
TL;DR: In this article, it was shown that the laser model process converges weakly in the sense of the matrix elements to a quantum diffusion whose equation is explicitly obtained, in the same sense as the Heisenberg evolution of an observable of the system to the solution of a quantum Langevin equation.
Abstract: We show that, in the weak coupling limit, the laser model process converges weakly in the sense of the matrix elements to a quantum diffusion whose equation is explicitly obtained. We prove convergence, in the same sense, of the Heisenberg evolution of an observable of the system to the solution of a quantum Langevin equation. As a corollary of this result, via the quantum Feynman-Kac technique, one can recover previous results on the quantum master equation for reduced evolutions of open systems. When applied to some particular model (e.g. the free Boson gas) our results allow to interpret the Lamb shift as an Ito correction term and to express the pumping rates in terms of quantities related to the original Hamiltonian model.
144 citations
142 citations
TL;DR: The factors limiting VO2max in humans are analyzed according to a multifactorial model derived from the O2 conductance equation, and tissue O2 transfer and mitochondrial O2 utilization are considered to be limiting.
126 citations
TL;DR: In this paper, the authors showed that most metal carbides or slicides can be synthesized at room temperature, by ball milling mixtures of elemental powders for some tens of hours with a vibratory mill.
Abstract: Most metal carbides or slicides may be synthesized at room temperature, by ball milling mixtures of elemental powders for some tens of hours with a vibratory mill. Both stable and metastable compounds containing a high density of defects can be obtained. In general, phases stable at low temperatures are synthesized. This observation allows us to confirm recent estimations for the maximum temperature (∼600 K) attained in these powders during mechanical alloying. Exceptions are found for some MSi2 suicides with M = titanium, iron or molybdenum for which both low- and high-temperature phases are formed.
106 citations
TL;DR: The equimolar mixture of dY24 and dR11 co-migrate in a poly-acrylamide gel and exhibits a thermally induced co-operative transition, which appears to be monophasic, reversible and concentration dependent.
Abstract: The equimolar mixture of d(CTCTTCTTTCTTTTCTTTCTTCTC) (dY24) and d(GAGAAGAAAGA) (dR11) [designated (dY24).(dR11)], forms at pH = 5 a DNA triplex, which mimicks the H-DNA structure. The DNA triplex was identified by the following criteria: (i) dY24 and dR11 co-migrate in a poly-acrylamide gel, with a mobility and a retardation coefficient comparable to those observed for an 11-triad DNA triplex, previously characterized in our laboratories (1); (ii) the intercalator ethidium bromide shows a poor affinity for (dR11).(dY24) at pH = 5, and a high affinity at pH = 8; (iii) the (dR11).(dY24) mixture is not a substrate for DNase I at pH = 5; (iv) the CD spectrum of (dR11).(dY24), at pH = 5, is consistent with those previously reported for triple-stranded DNA. The (dR11).(dY24) mixture exhibits a thermally induced co-operative transition, which appears to be monophasic, reversible and concentration dependent. This transition is attributed to the disruption of the DNA triplex into single strands. The enthalpy change of the triplex-coil transition was measured by DSC (delta Hcal = 129 +/- 6 kcal/mol) and, assuming a two-state model, by analysis of UV-denaturation curves (average of two methods delta HUV = 137 +/- 13 kcal/mol). Subtracting from delta Hcal of triplex formation the contributions due to the Watson-Crick helix and to the protonation of the C-residues, we found that each pyrimidine binding into the major groove of the duplex, through a Hoogsteen base pair, is accompanied by an average delta H = -5.8 +/- 0.6 kcal/mol. The effect on the stability of the (dR11).(dY24) triplex due to the substitution of a T:A:T triad with a T:T:T one was also investigated.
103 citations
01 Jan 1990
TL;DR: In this article, sufficient conditions for the validity of the maximum principle for cooperative and non-cooperative elliptic systems are given. But these conditions are not applicable to non-collaborative systems.
Abstract: In this paper we obtain some sufficient (necessary) conditionsfor the validity of the maximum principle for cooperative and non-cooperative elliptic systems.
76 citations
TL;DR: In this paper, the DELPHI detector at the e+e− storage ring LEP at the center of mass energies around 91.5 GeV was used to measure the production rates for 2-, 3-, 4, and 5-jet hadronic final states.
62 citations
Journal Article•
TL;DR: The enzymatic pattern of five enzymes involved in the purine salvage pathway, namely purine nucleoside phosphorylase, has been evaluated both in human intestinal and breast carcinomas and compared to that of normal tissues and a higher level of hypoxanthine-guanine phosphoribosyltransferase was associated with tumor tissues.
Abstract: The enzymatic pattern of five enzymes involved in the purine salvage pathway, namely purine nucleoside phosphorylase (EC 2.4.2.1), adenosine deaminase (EC 3.5.4.4), 5'-nucleotidase (EC 3.1.3.5), alkaline phosphatase (EC 3.1.3.1), and hypoxanthine-guanine phosphoribosyltransferase (EC 2.4.2.8) has been evaluated both in human intestinal and breast carcinomas and compared to that of normal tissues. A higher level of hypoxanthine-guanine phosphoribosyltransferase was associated with tumor tissues. This metabolic alteration should lead to an elevated synthesis of nucleotides in cancer cells, might confer selective growth advantages to neoplastic tissues, and account, at least in part, for the difficulties encountered in the chemotherapy of human tumors, by using compounds affecting only the purine de novo biosynthesis.
59 citations
TL;DR: In this paper, the correlations in rapidity in hadron production from e + e − annihilation near the Z 0 resonance were studied by means of the method of factorial moments, using data taken with the DELPHI detector at LEP.
55 citations
TL;DR: A measurement of the cross section for e+e- → hadrons using 11 000 hadronic decays of the Z boson at ten different center-of-mass energies is presented in this article.
TL;DR: In this article, the problem of control in the presence of unknown but limited disturbance for a discrete-time linear system with polyhedral input and state bounds is investigated, and a computational procedure for the control synthesis is proposed which can be implemented to obtain a feedback control.
Abstract: The problem of control in the presence of unknown but limited disturbance for a discrete-time linear system with polyhedral input and state bounds is investigated. Two problems are considered: that of reaching an assigned target set in the state space; and that of keeping the state in a given region using the available controls. In both cases, a solution is given via linear programming. A computational procedure for the control synthesis is proposed which can be implemented to obtain a feedback control.
TL;DR: In this paper, the stability analysis of Volterra-runge-kutta methods based on the basic test equation of the form y(t)=1+λ∫ 0 t [λ+σ(t−s)]y(s)ds (t≥0), where λ and σ are real parameters, is presented.
Abstract: Stability analysis of Volterra-Runge-Kutta methods based on the basic test equation of the form y(t)=1+λ∫ 0 t y(s)ds (t≥0), where λ is a complex parameter, and on the convolution est equation y(t)=1+∫ 0 t [λ+σ(t−s)]y(s)ds (t≥0), where λ and σ are real parameters, is presented. General stability conditions are derived and applied to construct numerical methods with good stability properties. In particular, a family of second-order V 0 -stable Volterra-Runge-Kutta methods is obtained
TL;DR: In this article, a search for the neutral Higgs boson in Z0-decays has been performed using the DELPHI detector at the large Electron Positron collider (LEP) at CERN.
TL;DR: In this paper, the authors search for the production of sleptons and gauginos in the two-prong decays of Z0, but no candidate remains after straightforward selections.
Argonne National Laboratory1, Fermilab2, University of Iowa3, Kyoto University4, Kyoto Sangyo University5, University of Occupational and Environmental Health Japan6, University of California, Berkeley7, Los Alamos National Laboratory8, University of Messina9, University of Minnesota10, Northwestern University11, Rice University12, University of Texas at Austin13, University of Udine14
10 May 1990-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this article, a new polarized-proton and -antiproton beam with 185-GeV/c momentum in the Fermilab MP beam line is described, which uses the parityconserving decay of lambda and antilambda hyperons to produce polarized protons and antiprotons, respectively.
Abstract: We describe a new polarized-proton and -antiproton beam with 185-GeV/c momentum in the Fermilab MP beam line which is currently operational. The design uses the parity-conserving decay of lambda and antilambda hyperons to produce polarized protons and antiprotons, respectively. A beam-transport system minimizes depolarization effects and uses a set of 12 dipole magnets that rotate the beam-particle spin direction. A beam-tagging system determines the momentum and polarization of individual beam particles, allowing a selection of particles in definite intervals at momentum and polarization. We measured polarization of the beam by using two types of polarimeters, which verified the determination of polarization by a beam-particle tagging system. Two of these processes are the inverse-Primakoff effect and the Coulomb-nuclear interference (CNI) in elastic proton-proton scattering. Another experiment measured the {pi}{sup 0} production asymmetry of large-x{sub F} values; this process may now be used as an on-line beam polarimeter. 9 refs., 9 figs.
TL;DR: In this article, the authors search for the production of charged scalars, primarily charged Higgs particles, decaying into c sc s, τν + jets, and τντν.
TL;DR: In this article, mixed mode experiments over symmetrically notched beams of concrete are discussed with reference to a possible size-scale transition and compared with existing results, where the beam was loaded to failure using crackmouth sliding-displacement control.
TL;DR: In this paper, the authors measured the cross section ratios R l = σ l (e + e − →l + l − ) σ h ( e + e−→l+l−) for l=e, μ and τ using data taken from a scan around the Z0.12.
TL;DR: Results show that during NADH oxidation iron ions undergo oxidoreduction and that hydrogen peroxide is produced and rapidly consumed.
Journal Article•
TL;DR: This technique might be suitable for ex vivo bone purging in an appropriate clinical setting, such as autologous bone marrow transplantation, and in cell suspensions composed of 90% normal bone marrow cells and 10% multidrug resistance-positive cells.
Abstract: Selective elimination f multidrug resistance-positive cells (LoVo/Dx) was obtained by using the monoclonal antibody MRK 16, which recognizes a surface epitope of the M r 170,000 glycoprotein, and a sheep antimouse immunoglobulin antibody, conjugated to the ribosome-inactivating protein saporin 6. The killing was greatly decreased or even abolished by adding the monoclonal antibody at a 100-fold concentration. Both the MRK 16 and anti-mouse saporin 6 conjugate did not show any killing activity when they were used separately. In cell suspensions composed of 90% normal bone marrow cells and 10% multidrug resistance-positive cells, the monoclonal antibody MRK 16 followed by the anti-mouse immunotoxin caused the elimination of 99% multidrug resistance-positive cells, as revealed by immunofluorescence and immunocytochemistry as well as by a clonal assay. Human normal hematopoietic precursors (granulomonocytic colony-forming units, erythroid burst-forming units, and multipotent granulomonocytic, erythroid, and megakaryocytic-forming units) were not affected by the MRK 16 plus immunotoxin treatment. This technique might be suitable for ex vivo bone purging in an appropriate clinical setting, such as autologous bone marrow transplantation.
TL;DR: In this paper, the CP MAS 13 C NMR spectra indicate that the γ-iPP packing mode is consistently different from the one of α-IPP, confirming the X-ray diffraction interpretation, and that the respective chemical shifts of the methyl resonances in the three crystalline phases of iPP can be rationalized in terms of the corresponding steric crowding statistically estimated on the basis of pertinent interlayer distances.
Abstract: The CP MAS 13 C NMR spectra indicate that the γ-iPP packing mode is consistently different from the one of α-iPP, confirming the X-ray diffraction interpretation, and that the respective chemical shifts of the methyl resonances in the three crystalline phases of iPP can be rationalized in terms of the corresponding steric crowding statistically estimated on the basis of pertinent interlayer distances
TL;DR: CuPUPY proved to be less toxic to human lymphocytes than to K562 cells, and this selectivity may be related to the low content of antioxidative enzymes in K562 Cells.
TL;DR: In this paper, the numerical solution of the elastic frictionless contact problem is obtained by means of boundary discretization techniques in the presence of both bilateral and unilateral constraints, and it is proved that the coerciveness (but not the symmetry) of the continuum problem is preserved when standard B.E.Ms are employed.
Abstract: In this paper the numerical solution of the elastic frictionless contact problem is obtained by means of boundary discretization techniques. Variational formulations in terms of boundary tractions are given in presence of both bilateral and unilateral constraints. The discretization of the boundary functional is examined from the point of view of the theory of approximation and it is proved that the coerciveness (but not the symmetry) of the continuum problem is preserved when standard B.E.Ms are employed. As a consequence, the contact problem can be cast as a L.C.P. having, as coefficient matrix, a generally non symmetric P matrix. A simple, but meaningful example is discussed in some detail.
TL;DR: In this paper, a search was made for pairs of scalar quarks (squarks) produced in e+e− annihilations at LEP and decaying into a standard quark and a neutral, non-interacting, stable, massive particle (the lightest supersymmetric particle, LSP).
TL;DR: The phenotype of strains affected in the OutB function indicates that this B. subtilis gene may be involved in nitrogen utilization, and the deduced gene products had 52% identical amino acids.
Abstract: The Bacillus subtilis outB gene was found to have strong similarities to an Escherichia coli gene complementing ntr-like mutations in Rhodobacter capsulatus. The deduced gene products had 52% identical amino acids (65% similar residues). The phenotype of strains affected in the OutB function indicates that this B. subtilis gene may be involved in nitrogen utilization.
TL;DR: In this article, the problem of deciding whether a module is a homomorphic image of a finite direct sum of uniserial modules is solved, i.e., a module which is both a homomorphism of a direct sum and a sub-module of a submodule of the sum of all uniserials.
Abstract: Let R be an associative ring with 1. A left R module M is uniserial i f the lattice L(M) of its submodules is totally ordered under inclusion. We give an example of a uniserial module M with the property of having two submodules 0 < H < K < M such that M is isomorphic to K/H (we call a module M with this property shrinkable). Then we give an example of a uniserial module M isomorphic to all its nonzero quotients M/N, N
TL;DR: The reaction between alkyl nitrites, particularly n-butyl nitrite, and tertiary aromatic amines under a variety of experimental conditions promptly yielded products of N-dealkylation-N-nitrosation, ring nitration, ipso-substitution and, occasionally, combinations of these processes.