Forced oscillations of a body attached to a viscoelastic rod of fractional derivative type

We study forced oscillations of a rod with a body attached to its free end so that the motion of a system is described by two sets of equations, one of integer and the other of the fractional order. To the constitutive equation we associate a single function of complex variable that plays a key role in finding the solution of the system and in determining its properties. This function could be defined for a linear viscoelastic bodies of integer/fractional derivative type

On a system of equations arising in viscoelasticity theory of fractional type

We study a system of partial differential equations with integer and fractional derivatives arising in the study of forced oscillatory motion of a viscoelastic rod. We propose a new approach considering a quotient of relations appearing in the constitutive equation instead the constitutive equation itself. Both, a rod and a body are assumed to have finite mass. The motion of a body is assumed to be translatory. Existence and uniqueness for the corresponding initial-boundary value problem is proved within the spaces of functions and distributions

Nano and viscoelastic Beck's column on elastic foundation

Beck's type column on Winkler type foundation is the subject of the present analysis. Instead of the Bernoulli-Euler model describing the rod, two generalized models will be adopted: Eringen non-local model corresponding to nano-rods and viscoelastic model of fractional Kelvin-Voigt type. The analysis shows that for nano-rod, the Herrmann-Smith paradox holds while for viscoelastic rod it does not

Space-time fractional Zener wave equation

Space-time fractional Zener wave equation, describing viscoelastic materials obeying the time-fractional Zener model and the space-fractional strain measure, is derived and analyzed. This model includes waves with finite speed, as well as non-propagating disturbances. The existence and the uniqueness of the solution to the generalized Cauchy problem are proved. Special cases are investigated and numerical examples are presented

Acute coronary syndrome in diclofenac sodium-induced type I hypersensitivity reaction : Kounis syndrome

Drug-induced type I hypersensitivity reactions are frequent. Sometimes, acute coronary syndrome (ACS) can be registered in such patients, which may have a serious impact on the course and management of the allergic reaction. Because of potentially atypical ACS clinical presentations, the ECG is an obligatory diagnostic tool in any allergic reaction. Coronary artery spasm is the pathophysiological basis of ACS, triggered by the action of potent vasoactive mediators (histamine, neutral proteases, arachidonic acid products) released from the cells involved in type I hypersensitivity. Allergic angina and allergic myocardial infarction are referred to as Kounis Syndrome. We describe herein a case of ACS in a patient with registered systemic immediate hypersensitivity reaction which developed following the muscular administration of diclofenac sodium.peer-reviewe

Impaired Insulin sensitivity and Insulin secretion in Haemodialysis patients with and without Secondary Hyperparathyroidism

The aim of our study was to investigate insulin sensitivity and beta cell function in hemodialysis (HD) patients without diabetes. We hypothesized that parathyroid gland function was a determinant of insulin sensitivity and/or beta cell function. The study was a randomized, cross-sectional one and patients were divided into two groups (total 27 patients), Gp.1 being those with relative hypoparathyroidism (iPTH<200 pg/ml) ­ 9 (33.3%), Gp.2 those with hyperparathyroidism (iPTH200 pg/ml) ­ 18 (66.6%) with Gp.3 (consisting of 43 healthy subjects acting as controls). Insulin resistance and insulin secretion were calculated from fasting serum insulin and glucose concentrations by the Homeostatic Model Assessment score (HOMA IR and HOMA BETA). The value of HOMA IR (3.28±1.3 for Gp.1, 4.80±2.4 for Gp.2, 1.70±0.8 for Gp.3) as well as the glucose level (5.0±1.0mmol/l in Gp.1, 5.2±0.8mmol/ l in Gp.2, 4.6±0.4mmol/l in Gp.3) was significantly higher in HD patients than in control subjects. Excessive insulin secretion was present in HD patients (as assessed by HOMA BETA) significantly higher only in Gp.1 (p=0.02).peer-reviewe

The effect of nitrogen fertilization on quality and yield of grass-legume mixtures

Studies were carried out in pure stands of three grasses: cocksfoot, meadow fescue and perennial ryegrass, and lucerne, as well as their mixtures with different ratios of individual components. The trial was carried out on an experimental field of the Institute for Animal Husbandry (Belgrade, Serbia). Fertilization with N caused a significant increase of yield. The highest yields were determined in treatments with 100 kg N ha(-1), and the lowest in treatments without fertilization. Fertilization increased significantly the CP content, but without impact on other quality parameters. CP, NDF and ADF differed significantly in various crops

Dry Matter Variability and Quality in Some Perspective Populations of some Agrostis Species

Important goals in forage grass breeding are improvement in forage yield and quality. The objective of this study was the examination of dry matter variability of autochtonous populations of three species from the genus Agrostis L. in order to choose the best ones for creating cultivars. Since we have not had domestic cultivars of these species so far, and it is known that they can be used for various purposes like cutting and grazing and having good quality, this research is made reasonable in many ways. The present results refer to the variability of genetic potentiality of the dry matter production in the year of usage. They refer to the basic parameters of quality on the chosen families originating from 14 populations of colonial bentgrass, Agrostis capillaris L., 22 populations creeping bentgrass, Agrostis stolonifera L. and 7 families originating from redtop, Agrostis gigantea Roth. With all the three species, the most productive family, with statistically significant higher yield, present the initial material for creating the first cultivars in our country