Research of dynamic RQ system M/M/1 with unreliable server

The paper considers a single-line retrial queueing (RQ) system with an unreliable server controlled by a dynamic random multiple access protocol. A study of the prelimit probability distribution of the number of applications in orbit has been carried out. To study this system, the method of generating functions is used

Asymptotic analysis of MMPP/M/1 retrial queueing system with unreliable server

In this paper, we study a single-server retrial queueing system with arrival Markov Modulated Poisson Process and an exponential law of the service time on an unreliable server. If the server is idle, an arrival customer occupies it for the servicing. When the server is busy, a customer goes into the orbit and waits a random time distributed exponentially. It is assumed that the server is unreliable, so it may fail. The server’s repairing and working times are exponentially distributed. The method of asymptotic analysis is proposed to find the stationary distribution of the number of customers in the orbit. It is shown that the asymptotic probability distribution under the condition of a long delay has the Gaussian form with obtained parameters

An Inverse Method to Obtain Porosity, Fibre Diameterand Density of Fibrous Sound Absorbing Materials

Characterization of sound absorbing materials is essential to predict its acoustic behaviour. The most commonly used models to do so consider the flow resistivity, porosity, and average fibre diameter as parameters to determine the acoustic impedance and sound absorbing coefficient. Besides direct experimental techniques, numerical approaches appear to be an alternative to estimate the material's parameters. In this work an inverse numerical method to obtain some parameters of a fibrous material is presented. Using measurements of the normal incidence sound absorption coefficient and then using the model proposed by Voronina, subsequent application of basic minimization techniques allows one to obtain the porosity, average fibre diameter and density of a sound absorbing material. The numerical results agree fairly well with the experimental data.This work has been supported by the Ministerio de Educacion y Ciencia-D.G. Investigacion (BIA2007-68098-C02-01 and BIA2007-68098-C02-02) and also from the Spanish Ministry of Foreign Affairs and Cooperation through the Inter-University and Scientific Research Cooperation Program (A/023748/09).Alba Fernández, J.; Rey Tormos, RMD.; Ramis Soriano, J.; Arenas, JP. (2011). An Inverse Method to Obtain Porosity, Fibre Diameterand Density of Fibrous Sound Absorbing Materials. Archives of Acoustics. 36(3):561-574. https://doi.org/10.2478/v10168-011-0040-xS561574363Allard, J., & Champoux, Y. (1992). New empirical equations for sound propagation in rigid frame fibrous materials. The Journal of the Acoustical Society of America, 91(6), 3346-3353. doi:10.1121/1.402824Attenborough, K. (1983). Acoustical characteristics of rigid fibrous absorbents and granular materials. The Journal of the Acoustical Society of America, 73(3), 785-799. doi:10.1121/1.389045Bies, D. A., & Hansen, C. H. (1980). Flow resistance information for acoustical design. Applied Acoustics, 13(5), 357-391. doi:10.1016/0003-682x(80)90002-xChampoux, Y., Stinson, M. R., & Daigle, G. A. (1991). Air‐based system for the measurement of porosity. The Journal of the Acoustical Society of America, 89(2), 910-916. doi:10.1121/1.1894653Crocker, M. J., & Arenas, J. P. (s. f.). Use of Sound-Absorbing Materials. Handbook of Noise and Vibration Control, 696-713. doi:10.1002/9780470209707.ch57Delany, M. E., & Bazley, E. N. (1970). Acoustical properties of fibrous absorbent materials. Applied Acoustics, 3(2), 105-116. doi:10.1016/0003-682x(70)90031-9Dunn, I. P., & Davern, W. A. (1986). Calculation of acoustic impedance of multi-layer absorbers. Applied Acoustics, 19(5), 321-334. doi:10.1016/0003-682x(86)90044-7Fellah, Z. E. A., Berger, S., Lauriks, W., Depollier, C., Aristégui, C., & Chapelon, J.-Y. (2003). Measuring the porosity and the tortuosity of porous materials via reflected waves at oblique incidence. The Journal of the Acoustical Society of America, 113(5), 2424-2433. doi:10.1121/1.1567275Fellah, Z. E. A., Berger, S., Lauriks, W., Depollier, C., & Fellah, M. (2003). Measuring the porosity of porous materials having a rigid frame via reflected waves: A time domain analysis with fractional derivatives. Journal of Applied Physics, 93(1), 296-303. doi:10.1063/1.1524025Fellah, Z. E. A., Berger, S., Lauriks, W., Depollier, C., Trompette, P., & Chapelon, J. Y. (2003). Ultrasonic measurement of the porosity and tortuosity of air-saturated random packings of beads. Journal of Applied Physics, 93(11), 9352-9359. doi:10.1063/1.1572191Fellah, Z. E. A., Mitri, F. G., Fellah, M., Ogam, E., & Depollier, C. (2007). Ultrasonic characterization of porous absorbing materials: Inverse problem. Journal of Sound and Vibration, 302(4-5), 746-759. doi:10.1016/j.jsv.2006.12.007Garai, M., & Pompoli, F. (2005). A simple empirical model of polyester fibre materials for acoustical applications. Applied Acoustics, 66(12), 1383-1398. doi:10.1016/j.apacoust.2005.04.008ISO (1998), 10534-2:1998. Acoustics - determination of sound absorption coefficient and impedance in impedance tubes - Part 2: transfer-function method, International Organization for Standardization, Geneva.Miki, Y. (1990). Acoustical properties of porous materials. Modifications of Delany-Bazley models. Journal of the Acoustical Society of Japan (E), 11(1), 19-24. doi:10.1250/ast.11.19Miki, Y. (1990). Acoustical properties of porous materials. Generalizations of empirical models. Journal of the Acoustical Society of Japan (E), 11(1), 25-28. doi:10.1250/ast.11.25Ramis, J., Alba, J., Del Rey, R., Escuder, E., & Sanchís, V. J. (2010). Nuevos materiales absorbentes acústicos basados en fibra de kenaf. Materiales de Construcción, 60(299), 133-143. doi:10.3989/mc.2010.50809Shoshani, Y., & Yakubov, Y. (2000). Numerical assessment of maximal absorption coefficients for nonwoven fiberwebs. Applied Acoustics, 59(1), 77-87. doi:10.1016/s0003-682x(99)00015-8Umnova, O., Attenborough, K., Shin, H.-C., & Cummings, A. (2005). Deduction of tortuosity and porosity from acoustic reflection and transmission measurements on thick samples of rigid-porous materials. Applied Acoustics, 66(6), 607-624. doi:10.1016/j.apacoust.2004.02.005Voronina, N. (1994). Acoustic properties of fibrous materials. Applied Acoustics, 42(2), 165-174. doi:10.1016/0003-682x(94)90005-1Voronina, N. (1996). Improved empirical model of sound propagation through a fibrous material. Applied Acoustics, 48(2), 121-132. doi:10.1016/0003-682x(95)00055-eVoronina, N. (1998). An empirical model for elastic porous materials. Applied Acoustics, 55(1), 67-83. doi:10.1016/s0003-682x(97)00098-4Voronina, N. (1999). An empirical model for rigid-frame porous materials with low porosity. Applied Acoustics, 58(3), 295-304. doi:10.1016/s0003-682x(98)00076-0Voronina, N. ., & Horoshenkov, K. . (2003). A new empirical model for the acoustic properties of loose granular media. Applied Acoustics, 64(4), 415-432. doi:10.1016/s0003-682x(02)00105-6Wang, X., Eisenbrey, J., Zeitz, M., & Sun, J. Q. (2004). Multi-stage regression analysis of acoustical properties of polyurethane foams. Journal of Sound and Vibration, 273(4-5), 1109-1117. doi:10.1016/j.jsv.2003.09.039Wilson, D. K. (1997). Simple, relaxational models for the acoustical properties of porous media. Applied Acoustics, 50(3), 171-188. doi:10.1016/s0003-682x(96)00048-

Immune status of the lupus-test positive patients

Розглянуто зміни показників імунного статусу пацієнтів, позитивних за люпус-тестом. Охарактеризовано експресію деяких рецепторів на поверхні лімфоцитів периферійної крові. Розраховано кореляцію для показників тесту відновлення тетразолію нітросинього та рівня експресії CD95-рецептора (рецептора апоптозу). Розглянуто зміни показників імунного статусу пацієнтів, позитивних за люпус-тестом. Охарактеризовано експресію деяких рецепторів на поверхні лімфоцитів периферійної крові. Розраховано кореляцію для показників тесту відновлення тетразолію нітросинього та рівня експресії CD95-рецептора (рецептора апоптозу). Changes in immune status of the lupus-test positive patients are presented. The expression of some lymphocytic surface receptors in the peripheral blood is characterised. Correlation between the NST-test index and the level of CD95-receptor expression (apoptosis receptor) was calculated.

Стан біохімічних систем крові білих щурів в умовах алкогольного ураження печінки та профілактичної дії метадоксину

It was developed model of alcoholic hepatitis by intragastric administration of 40 % ethanol at a dose of 7 ml/kg body weight of male Wistar rats for 7 days. As a biochemical marker of alcoholic hepatitis were used indicators of cytolytic syndrome (activity of alanine aminotransferase, aspartate aminotransferase, catalase), cholestatic syndromes (alkaline phosphatase, gamma glutamyl transpeptidase) and lipid exchange (levels of cholesterol, triglycerides). It was shown that metadoxine (ionic salt of pyridoxine and pyroglutamic acid), which was administered preventively intragastrically at a dose of 90 mg/kg 30 min prior to the administration of alcohol, normalized activity of aspartate aminotransferase and catalase; gamma-glutamyl transpeptidase; triglycerides. The lack of a positive influence of metadoxine on the other studied biochemical blood parameters indicatives that mechanisms of development of alcoholic hepatitis and course of its are different. It is assumed that the hepatoprotective effect of the drug is realized through antioxidant mechanism.Воспроизведена модель алкогольного гепатита путем внутрижелудочного введения 40% раствора этанола в дозе 7 мл/кг массы тела крыс самцов линии Вистар в течение 7 дней. В качестве биохимических маркеров алкогольного гепатита использованы показатели цитолитического синдрома (активность аланинаминотрансферазы, аспартатаминотрансферазы, каталазы), холестатического синдрома (активность щелочной фосфатазы, гамма-глутамилтранспептидазы) и липидного обмена (содержание холестерина, триглицеридов). Показано, что метадоксин (ионная соль пиридоксина и пироглутаминовой кислоты) при профилактическом введении внутрижелудочного в дозе 90 мг/кг за 30 минут до введения алкоголя нормализовал активность аспартатаминотрансферазы и каталазы; гамма-глутамилтранспептидазы; содержание триглицеридов. Отсутствие положительного влияния метадоксина на другие исследуемые биохимические показатели крови свидетельствует о различных механизмах возникновения алкогольного гепатита и его течения. Предполагается, что гепатопротекторное действие препарата опосредовано антиоксидантным механизмом.Відтворено модель алкогольного гепатиту шляхом внутрішньошлункового введення 40 % розчину етанолу в дозі 7 мл/кг маси тіла щурів-самців лінії Вістар протягом 7 днів. В якості біохімічних маркерів алкогольного гепатиту використані показники цитолітичного синдрому (активність аланінамінотрансферази, аспартатамінотрансферази, каталази), холестатичного синдрому (активність лужної фосфатази, гамма-глутамілтранспептидази) та ліпідного обміну (вміст холестерину, тригліцеридів). Показано, що метадоксин (іонна сіль піридоксину та піроглутамінової кислоти) при профілактичному введенні внутрішньошлунково в дозі 90 мг/кг за 30 хвилин до введення алкоголю нормалізував активність аспартатамінотрансферази та каталази; гамма-глутамілтранспептидази; вміст тригліцеридів. Відсутність позитивного впливу метадоксину на інші досліджувані біохімічні показники крові свідчить про різні механізми виникнення алкогольного гепатиту та його перебігу. Передбачається, що гепатозахисна дія препарату опосередкована антиоксидантним механізмом

Frailty and age dynamics of separate clinical indicators in patients of therapeutic profile

Age-related dynamics of body homeostasis individual indicators in patients with risk of developing frailty and without frailty was studied in the research. Clinical indicators mostly associated with age were determined: muscle strength, glomerular filtration rate, total protein, potassium, hemoglobin, alanine aminotransferase activity, and blood plasma glucose. The contribution of reduced overall renal function, as well as anabolic activity of the liver in the development of age-related changes and frailty was studie

New aminophosphonates (aminophosphine oxides) containing acetal groups in reactions with polyatomic phenols

© 2016 Taylor & Francis Group, LLC.A wide range of phosphorylated α-,β-,γ-aminoacetals of various structure were obtained by Kabachnik- Fields reaction. Acid-catalyzed reactions of phenols with α-,β-,γ -aminoacetals provide a new approach to the synthesis of different polyphenols, containing aminophosphonate and aminophosphine oxide moieties, arylsubstituted heterocycles containing phosphonate and phosphinoxide groups. Herein we present a short overview of these reactions

Genetic polymorphism of CYP1A1 and CYP2D6 in populations of Buryats, Teleuts and Russians of Eastern Siberia

The study of the gene polymorphism of the system of biotransformation of xenobiotics is an important area of modern medical and genetic research. The aim of this work is to study the frequency of the alleles of the CYP1A1 (A2455G (*2C), rs1048943), CYP2D6 (A2549del (*3), rs35742686); G1846A (*4), rs3892097) genes of Teleuts (n = 115), Eastern Buryats (n = 132), Western Buryats (n = 280), their Métis (n = 56), and Russians of East Siberia (n = 122). Genotyping was performed using real-time PCR with competitive TaqMan allele-specific probes. The frequency of the CYP1A1*2C (2455G) allele was 28.8 % in the Eastern Buryat, 34.6 % in the Western Buryat, 16.7 % in the Teleut, and 31.3 % in the Métis cohort. The frequency of CYP1A1*2C (2455G) in the Russians of Eastern Siberia (4.1 %) corresponds to the frequency range found in European populations. A high-frequency occurrence of CYP1A1*2C (2455G) among Buryats and Teleuts may be indicative of a higher population-wide risk of diseases influenced by technogenic pollutants – substrates of CYP1A1. The CYP2D6*3 (2549del) allele was not detected in cohorts of indigenous populations, among Russians it was 0.4 %, and it was 2.7 % among Métis. The frequency of CYP2D6*4 (1846A) in Eastern and Western Buryats was 5.3 % and 4.3 %, respectively, for Teleuts it was 7.4 %. It was significantly higher in the Russian population (12 %), and among Métis (9.8 %). The obtained data makes it possible to predict a reduced risk of side effects of drugs and cancer associated with CYP2D6*3 (2549del) and CYP2D6*4 (1846A) in the Buryat and Teleut populations. However, metisation introduces new polymorphic variants into indigenous populations, shifts gene frequencies and changes the degree of risks