The purpose of this study was to determine if there is flowmediated vasodilation of the femoral artery in response to progressive increases in flow within a physiological range observed in the in vivo experiments. Femoral artery blood flow was determined in conscious rabbits (n=5) using chronically implanted flowprobes. Resting blood flow was 8.3±0.6 ml/min and increased to 39.9±5.4 ml/min during high intensity exercise. Femoral arteries (n=12, 1705±43 μm outer diameter) harvested from a separate group of rabbits were mounted on cannulas and diameter was continuously monitored by video system. Functional integrity of the endothelium was tested with acetylcholine. The arteries were set at a transmural pressure of 100 mm Hg and preconstricted with phenylephrine to 73±3 % of initial diameter. Using a roller pump with pressure held constant, the arteries were perfused intraluminally with warmed, oxygenated Krebs' solution (pH=7.4) over a physiological range of flows up to 35 ml/min. As flow increased from 5 ml/min to 35 ml/min, diameter decreased significantly (p<0.05) from 1285±58 μm to 1100±49 μm. Thus, in vessels with a functional endothelium, increasing intraluminal flow over a physiological range of flows produced constriction, not dilation. Based on these results, it seems unlikely that flow-mediated vasodilation in the rabbit femoral artery contributes to exercise hyperemia., P. S. Clifford ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Five Trichoptera species, representing four different families of three suborders, have been examined for sex chromatin status in relation to their sex chromosome system. These were Hydropsyche sp., Polycentropus flavomaculatus (Pictet), Rhyacophila sp., Anabolia furcata Brauer and Limnephilus decipiens (Kolenatý). None of the species displayed sex-specific heterochromatin in highly polyploid nuclei of the Malpighian tubule cells. Such sex chromatin is a characteristic trait of the heterogametic female sex in the sister order Lepidoptera; it is derived from the heterologous sex chromosome W. Hence, the absence of sex chromatin in somatic nuclei of Trichoptera females indicated the lack of a W chromosome in their karyotype. Correspondingly, diploid chromosome sets of the females consisted of an odd chromosome number, two sets of autosomes and one sex chromosome Z. Thus, the Z/ZZ chromosome mechanism of sex determination has been confirmed. In pachytene and postpachytene oocytes, the Z chromosome having no pairing partner formed a univalent. In Hydropsyche sp., the Z-univalent was distinct as a compact, positively heteropycnotic element. Whereas, in two other caddis-flies, P. flavomaculatus and L. decipiens, it formed a negatively heteropycnotic thread. In postpachytene nuclei of nurse cells of A. furcata, two sister chromatids of the Z chromosome separated as a result of chromosome degeneration and formed a negatively heteropycnotic pseudobivalent. The species-specific differences in pycnosis may reflect a transcriptional activity/inactivity of the Z chromosome during meiotic prophase. The absence of sex chromatin and the sex chromosome system in Trichoptera are characters in common with the "primitive" Lepidoptera. This supports a hypothesis that the commcommon with the "primitive" Lepidoptera. This supports a hypothesis that the common ancestor of both orders had a ZJZZ sex chromosome
mechanism.
Absolute continuity for functionals is studied in the context of proper and abstract Riemann integration examining the relation to absolute continuity for finitely additive measures and giving results in both directions: integrals coming from measures and measures induced by integrals. To this end, we look for relations between the corresponding integrable functions of absolutely continuous integrals and we deal with the possibility of preserving absolute continuity when extending the elemental integrals.
A two dimensional stochastic differential equation is suggested as a stochastic model for the Kermack-McKendrick epidemics. Its strong (weak) existence and uniqueness and absorption properties are investigated. The examples presented in Section 5 are meant to illustrate possible different asymptotics of a solution to the equation.
We prove that the spectral sets of any positive abstract Riemann integrable function are measurable but (at most) a countable amount of them. In addition, the integral of such a function can be computed as an improper classical Riemann integral of the measures of its spectral sets under some weak continuity conditions which in fact characterize the integral representation.
Recently, we established some generalizations of the theory of Lagrange multipliers arising from nonlinear programming in Banach spaces, which enable us to treat not only elliptic problems but also parabolic problems in the same generalized framework. The main objective of the present paper is to discuss a typical time-dependent double obstacle problem as a new application of the above mentioned generalization. Actually, we describe it as a usual parabolic variational inequality and then characterize it as a parabolic inclusion by using the Lagrange multiplier and the nonlinear maximal monotone operator associated with the time differential under time-dependent double obstacles.
In this paper, we give a new approach to the study of Weyl-type theorems. Precisely, we introduce the concepts of spectral valued and spectral partitioning functions. Using two natural order relations on the set of spectral valued functions, we reduce the question of relationship between Weyl-type theorems to the study of the set difference between the parts of the spectrum that are involved. This study solves completely the question of relationship between two spectral valued functions, comparable for one or the other order relation. Then several known results about Weyl-type theorems become corollaries of the results obtained.