Showing papers by "Université de Sherbrooke published in 1985"
TL;DR: It is suggested that the site of action of several vasodilators is the endothelium, while other vasodILators and all the vasoconstrictors influence the arterial vessels tone presumably by acting on the smooth muscle cells.
176 citations
TL;DR: The magnitude of flicker noise, considered as resistance fluctuations, in random resistor networks are reported and the new exponent $\ensuremath{\kappa}$ is calculated by various methods: Monte Carlo simulations, effective-medium theory, and position-space renormalization group.
Abstract: New results for the magnitude of flicker noise, considered as resistance fluctuations, in random resistor networks are reported. Near the percolation threshold ${p}_{c}$, the magnitude of the relative noise is shown to diverge as ${(p\ensuremath{-}{p}_{c})}^{\ensuremath{-}\ensuremath{\kappa}}$. The new exponent $\ensuremath{\kappa}$ is calculated by various methods: Monte Carlo simulations, effective-medium theory, and position-space renormalization group. Exponents pertaining to higher-order cumulants of the resistance fluctuations are also calculated. The possible implications of our results for ongoing experiments on metal-insulator mixtures and cermets are also discussed.
162 citations
TL;DR: Marek Rola-Pleszczynski suggests that leukotrienes may play an important role in immunoregulation during inflammatory processes.
154 citations
TL;DR: In this article, the injection of powders into an inductively coupled plasma is modeled and the plasma-particle interaction and its effect on plasma fields is considered, and it is demonstrated that for most applications, such interactions must be considered in any model.
151 citations
TL;DR: A finite-size-scaling function is proposed, and the corresponding exponent b is calculated in mean-field theory, and an anomalous increase of the noise at p\ensuremath{\rightarrow}psubcsup+ is obtained.
Abstract: A general formulation for the spectral noise ${S}_{R}$ of random linear resistor networks of arbitrary topology is given. General calculational methods based on Tellegen's theorem are illustrated for one- and two-probe configurations. For self-similar networks, we show the existence of a new exponent b, member of a whole new hierarchy of exponents characterizing the size dependence of the normalized noise spectrum ${\mathrm{scrS}}_{R}$=${S}_{R}$/${R}^{2}$. is shown to lie between the fractal dimension d\ifmmode\bar\else\textasciimacron\fi{} and the resistance exponent -\ensuremath{\beta}subL. b has been calculated for a large class of fractal structures: Sierpi\ifmmode \acute{n}\else \'{n}\fi{}ski gaskets, X lattices, von Koch structures, etc. For percolating systems, scrSsubR is investigated for plpsubc as well as for pgpsubc. In particular, an anomalous increase of the noise at p\ensuremath{\rightarrow}psubcsup+ is obtained. A finite-size-scaling function is proposed, and the corresponding exponent b is calculated in mean-field theory.
122 citations
TL;DR: It is proved that certain classes of cutting stock problems have the integer round-up property and the proof of these results relies upon the decomposition properties of certain knapsack polyhedra.
Abstract: An integer programming problem is said to have the integer round-up property if its optimal value is given by the least integer greater than or equal to the optimal value of its linear programming relaxation In this paper we prove that certain classes of cutting stock problems have the integer round-up property The proof of these results relies upon the decomposition properties of certain knapsack polyhedra
106 citations
01 Jan 1985
TL;DR: The conversion of biomass materials into oils has a precise objective: to transform a carbonaceous solid material which is originally difficult to handle, bulky and of low energy concentration, into pumpable oils having physico-chemical characteristics which permit storage, transferability through pumping systems, and further use either in direct combustion furnaces or as feedstocks for hydrotreatment leading to specific fuels and chemicals as mentioned in this paper.
Abstract: The conversion of biomass materials into oils has a precise objective:
To transform a carbonaceous solid material which is originally difficult to handle, bulky and of low energy concentration, into pumpable oils having physico-chemical characteristics which permit storage, transferability through pumping systems, and further use either in direct combustion furnaces or as feedstocks for hydrotreatment leading to specific fuels and chemicals.
94 citations
TL;DR: Tetrasulfophthalocyanine and a series of its metal chelates were tested for their ability to photoinactivate V‐79 Chinese hamster cells and cerium was about 5 x more effective for cell killing than the metal free tetrasulfophile and 20 x more efficient as compared to hematoporphyrin.
Abstract: — Tetrasulfophthalocyanine and a series of its metal chelates were tested for their ability to photoinactivate V-79 Chinese hamster cells. Incubation of cells for 1 h with tetrasulfophthalocyanine at 5 μM effectively sensitized cells towards red light. At the 1% survival level, the dye was 4 x more efficient than hematoporphyrin, efficiency being defined in terms of drug concentration in the medium and incident light fluence rather than on the basis of quanta absorbed. Chelation of the dye with metal ions resulted in most cases in a greatly diminished photosensitizing effect, except for cerium. The cerium complex was about 5 x more effective for cell killing than the metal free tetrasulfophthalocyanine and 20 x more efficient as compared to hematoporphyrin. Hypoxic conditions resulted in total loss of photoactivity indicating the involvement of oxygen in the action mechanism. The inactivation by near-UV light by these drugs was also investigated. The potential of sulfonated phthalocyanines as novel photosensitizers for photodynamic cancer therapy is discussed.
87 citations
TL;DR: Hyper ADP-ribosylation of histone H2B is observed at NAD concentrations of 10 microM suggesting that histoneH2B can undergo the same type of ADp-ribsylation pattern as hist one H1, and an elongation of the polymer attached to the enzyme and other nuclear proteins takes place.
Abstract: The pattern of nucleosomal histones poly(ADP-ribosyl)ation is changed under conditions which affect the poly(ADP-ribosyl)ation state of the enzyme. At low NAD concentrations the enzyme can poly(ADP-ribosyl)ate histones H1 and H1°, H2A, A2A, and H2B. However at NAD concentrations above 10 μM the enzyme preferentially poly(ADP-ribosyl)ates histone H1 to a hyper ADP-ribosylated form. Furthermore we have observed hyper ADP-ribosylation of histone H2B at NAD concentrations of 10 μM suggesting that histone H2B can undergo the same type of ADP-ribosylation pattern as histone H1. Also at higher NAD concentrations an elongation of the polymer attached to the enzyme and other nuclear proteins takes place.
74 citations
TL;DR: In this paper, the entire load deformation history of a cylindrical tensile bar is computed using the finite element method in conjunction with hill's (1958, 1959) variational principle.
Abstract: N ecking and neck propagation as observed in polymers which “cold draw” is analyzed numerically for a circular cylindrical tensile specimen. The entire load-deformation history of the bar is computed using the finite element method in conjunction with hill's (1958, 1959) variational principle. Rate-independent elastic-plastic material behaviour is assumed. Results are given for the overall load-elongation response of the bar, as well as for the evolution of the specimen profile and the stress and strain distributions in the bar at various stages of the deformation process. The implications of our results on conventional methods used to analyze tension data for polymers are also discussed.
67 citations
TL;DR: It is established that human fetal small intestine can be maintained in organ culture for at least 9 days in a serum-free medium.
TL;DR: Analysis of the magnitude of the hyperventilation and the VE damping pre-hypoxic levels occurring with sustained hypoxia in newborns of various species suggests that the immaturity of the O2-sensitive chemoreceptor rather than the central effect of Hypoxia is the determinant factor of the diphasic response of newborn mammals to hypoxicHypoxia.
TL;DR: Chronic haloperidol treatment markedly increases dynorphin-related peptide contents in caudate-putamen, globus pallidus and substantia nigra and the Leu-enkephalin/dynorphin projection appears to be under striatal dopaminergic control.
TL;DR: In this article, a comparison is made of the performance of two different algorithms used for the computation of the flow and temperature fields in an inductively coupled plasma and the results show that the formulation of the mathematical model and the chosen numerical technique can substantially influence the stability and the convergence of the solution.
Abstract: A comparison is made of the performance of two different algorithms used for the computation of the flow and temperature fields in an inductively coupled plasma The first algorithm is based on the solutions of the two-dimensional continuity, momentum, and energy equations in terms of vorticity, stream function, and enthalpy The second one is based on the solution of the same equations in terms of the velocity, pressure, and enthalpy The results show that the formulation of the mathematical model and the chosen numerical technique can substantially influence the stability and the convergence of the solution
TL;DR: The results show that isolated intestinal cells from adult mice possess a high concentration of EGF receptors that exhibit kinetic properties identical to those of other EGF target cells.
Abstract: In isolated intestinal cells from adult fed mouse, the binding of [125I]epidermal growth factor (EGF) was time and temperature dependent. Maximum binding was obtained after 30 min of incubation at 20 C. For a concentration of 5 × 10−n m [125I]EGF (180 μCi/μg), specific binding for isolated cells from duodenum, jejunum, and ileum was closely similar, with means of 9.4 ± 0.9, 13.3 ± 0.8, and 9.3 ± 2.0%/mg protein, respectively. The binding increases along the crypt-villus axis. Inhibition dose-response analysis indicated high affinity binding with 50% inhibition at 3 × 10−10 m unlabeled EGF. The specific binding decreased by 19% after 48 h of fasting. In the P1 fraction (microsome and lateral membranes) from scrapings or isolated cells of the jejunal mucosa, specific binding was 2.4 ± 0.8 and 6.5 ± 0.7%/mg protein, respectively. In the P2 fraction (brush border), specific binding was 6.9 ± 1.6% and 16.3 ± 0.7%/mg protein. After 24 h of organ culture, specific binding is not modified in duodenal explants. Mo...
TL;DR: Findings with antagonists support the indication, emerged from the order of potency of agonists, that tachykinins may act on two and possibly three different receptor types.
TL;DR: The existence and multiplicity of T-periodic solutions of the forced pen-dulum equation have been considered recently by a number of authors and refer to as discussed by the authors for the history and a survey of this problem.
TL;DR: The results presented here demonstrate, for the first time, the presence of ACTH receptors in the zona glomerulosa of adrenal glands and the surprising result that the glomersulosa cells carry a higher concentration ofACTH receptors than the fasciculata cells.
Abstract: The results presented here demonstrate, for the first time, the presence of ACTH receptors in the zona glomerulosa of adrenal glands. We obtained the surprising result that the glomerulosa cells carry a higher concentration of ACTH receptors than the fasciculata cells. The analog [Phe2, Nle4]ACTH was iodinated by the iodogen method and separated by HPLC; it was obtained carrier-free and has a specific activity of 600 μCi/μg, retaining full biological potency. After 30 min of incubation at 22 C for concentrations of 2 × 10−11 m [125I]ACTH, specific binding values were 4.85 ± 0.44% (n = 15) and 1.85 ± 0.18% (n = 15), respectively, for 50,000 glomerulosa or fasciculata cells. For the glomerulosa, our results indicated a density of 6.5 × 104, receptors/cell of the high affinity type (Kd1 = 7.6 × 10×11 m) and 1.0 × 106 receptors of the low affinity type (Kd2 = 1.2 × 10−9 m). In the zona fasciculate, we found 7.2 × 103 receptors of high affinity (Kd1 = 1.1 × 10−11 m) per cell and 6.3 × 106 of low affinity (Kd2 ...
TL;DR: 67Ga lung uptake is an early indicator of chronic macrophagic alveolitis in asbestos workers, which usually progresses to asbestosis.
Abstract: To analyze the clinical features of asbestos-induced alveolitis and stage its activity, we evaluated 217 asbestos workers by the usual clinical, radiological, and functional parameters and computerized gallium 67(Ga) lung scan; we obtained bronchoalveolar lavage (BAL) in 33 and lung biopsy in 6. In addition, we scored the profusion of lung rales and correlated it with other parameters of severity of asbestosis. In the 55 workers without asbestosis and normal 67Ga scan, BAL analyses were comparable to those of controls. Of the 56 without asbestosis but increased 67Ga lung uptake, BAL analyses in 8 documented a predominantly macrophagic alveolitis (confirmed on lung biopsy in 3), with the highest levels of BAL fibronectin. In the 106 workers with asbestosis, 67Ga lung uptake was increased in 75; BAL in 17 demonstrated a macrophagic and neutro-philic alveolitis with elevated fibronectin levels. Lung biopsy in 3 of the latter workers documented peribronchiolar fibrosing alveolitis. Rale scores in all workers or in those without asbestosis did not correlate with 67Ga scores; they correlated fairly well with profusion of parenchymal opacities (Rs = 0.42) and rigidity of the lung pressure-volume curve (Rs = 0.39). Thus, 67Ga lung uptake is an early indicator of chronic macrophagic alveolitis in asbestos workers, which usually progresses to asbestosis. In the disease, profusion of lung rales constitutes a simple clinical mode of assessment of disease severity that correlates better with radiological and functional parameters than with parameters of alveolitis.
TL;DR: Their biodistribution in rabbits and tumor-bearing rats revealed that most of the radioactivity accumulated in the kidneys, liver, ovaries, adrenals and spleen.
TL;DR: In this paper, a quick clay soil from a site close to the Grande-Baleine River on the west bank of Hudson Bay has been resedimented artificially to simulate freshwater and marine environments.
Abstract: A quick clay soil from a site close to the Grande‐Baleine River on the west bank of Hudson Bay has been resedimented artificially. Specimens were formed at salinities of 0.2 and 35 g/L to simulate freshwater and marine environments. Under a consolidation pressure of 50 kPa, the specimens were shown to yield sensitivities from 5 to 26, the highest being for the low‐salinity specimens. The natural sensitivity (as measured with the fall cone) is greater than 300. The initial compressibility of soils formed at low salinity is lower than those at high salinity, but values at higher pressures converge with the compressibility of the intact soil. The sensitivity of the artificial soil is lower than that of the intact soil and reflects the greater structuration of the latter. For artificial soils, the sensitivity increases as the salinity decreases; this is due mostly to a reduction in the remolded strength. Results show that freshly deposited soils can have a high void ratio that results from a structur...
TL;DR: In this paper, the authors provided explicit expressions for the partial derivatives of the associated energy functional with respect to the coordinates xil, 1 ⩽ l l n, of each of the variable nodes Mi, i = 1,…, p.
TL;DR: Evidence is provided that multiple receptor types are involved in mediating the effects of tachykinins in peripheral organs and substance K was more effective than substance P in activating micturition.
TL;DR: The results of the present study demonstrate that neurotensin can affect hyperactivity elicited by a strong and persistent activation of mesolimbic dopamine receptors or by stimulation of events beyond these receptors.
TL;DR: In this article, a computer model was developed for the calculation of the two-dimensional emission pattern from a spectrochemical ICP, assuming local thermodynamic equilibrium (LTE), the flow, temperature and the concentration fields were computed.
TL;DR: Both agonists and antagonists appear to be useful for the characterization of tachykinins receptors; either the whole N-terminal portion of SP or a shorter sequence, modified in position 6, increase the antagonist affinity against NA in the SP-E receptor system of the rat duodenum.
TL;DR: In this paper, the equivalence between Fe[γ] and FP[γ], the universal energy functional defined in the domain E 1n of ensemble representable reduced first-order density operators γ, and Fp[γ, the corresponding functional over P1n, the set of pure state n-representable γ1s, is shown.
Abstract: The equivalence between Fe[γ] and FP[γ] over p1n is shown, where Fe[γ] is the universal energy functional defined in the domain E1n of ensemble representable reduced first-order density operators γ, and Fp[γ], the corresponding functional over P1n, the set of pure state n-representable γ1s. The construction of Fe[γ] or equivalently of Fp[γ]n over P1n is considered by imposing the explicit requirement that Γ, the nth-order density operator, map into γ; this condition is introduced into the variational functional by means of a matrix α of Lagrange multipliers. The ensuing functional F[γ] is then used in order to obtain the Euler-Lagrange equations for the one-matrix γ. For the purpose of illustrating the present formalism, an explicit derivation of the Hartree-Fock equations as a particular case of the general Euler-Lagrange equations obtained herein, is given.
TL;DR: In this paper, the Negative Eigenvalue Theorem and transfer matrix methods are considered within a unified framework and generalized to compute projected densities of states or, more generally, any linear combination of matrix elements of the inverse of large symmetric random matrices.
Abstract: It is shown that the Negative Eigenvalue Theorem and transfer matrix methods may be considered within a unified framework and generalized to compute projected densities of states or, more generally, any linear combination of matrix elements of the inverse of large symmetric random matrices. As examples of applications, extensive simulations for one- and two-mode behaviour in the Raman spectrum of one-dimensional mixed crystals and a finite-size scaling analysis of critical exponents for the central force percolation universality class are presented On demontre que le theoreme des valeurs propres negatives et les methodes de matrice de transfert peuvent etre consideres du meme point de vue unifie pour etre ensuite generalises au calcul des densites d'etats projetees ou plus generalement, au calcul de n'importe quelle combinaison lineaire d'elements de matrice de l'inverse de grandes matrices symetriques aleatoires. Application a la simulation des comportements a 1 et 2 modes du spectre Raman de cristaux mixtes 1D et a l'analyse de taille finie pour les exposants critiques de la classe d'universalite de percolation des forces centrales
TL;DR: In this article, a gamma-ray detector based on silicon avalanche photodiodes (APD) and bismuth germanate (BGO) scintillators is reported.
Abstract: Spectroscopic and timing characteristics of a gamma-ray detector based on silicon avalanche photodiodes (APD) and bismuth germanate (BGO) scintillators are reported. The APD used in this work is a large area (25 mm2) device of the "reach through" type having a quantum efficiency of 70% at 480 nm. When coupled to a 5×5×3 mm3 BGO crystal, its spectroscopic performance is found to be superior to that of a PMT coupled to the same crystal, owing largely to its higher quantum efficiency. At room temperature, the APD achieves better energy resolution than any other (unity gain) solid state photodetector currently available; at -15 °C, its spectroscopic performance is comnparable to that of large area p-i-n photodiodes at -150 °C. Preliminary measurements show that the timing performance of the new detector allows it to be used for both energy and coincidence discrimination in positron emission tomography (PET). Results obtained with a realistic BGO crystal shape and size for PET are also presented. Limitations and possible improvements are discussed.