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L. Figueroa-Valverde,F. Dı´az-Cedillo,E. Garcı´a-Cervera,E. Pool Go´mez,M. Lo´pez-Ramos,M. Rosas-Nexticapa,R. Martinez-Camacho 대한약학회 2013 Archives of Pharmacal Research Vol.36 No.10
Experimental studies indicate that some steroidderivatives have inotropic activity; nevertheless, there isscarce information about the effects of the dehydroisoandrosteroneand its derivatives at cardiovascular level. Inaddition, to date the cellular site and mechanism of actionof dehydroisoandrosterone at cardiovascular level is veryconfusing. In order, to clarify those phenomena in this study,a dehydroisoandrosterone derivative was synthesized withthe objective of to evaluate its activity on perfusion pressureand coronary resistance and compare this phenomenon withthe effect exerted by dehydroisoandrosterone. The Langendorfftechnique was used to measure changes on perfusionpressure and coronary resistance in an isolated rat heartmodel in absence or presence of dehydroisoandrosterone andits derivative. Additionally, to characterize the molecularmechanism involved in the inotropic activity induced bydehydroisoandrosterone derivative was evaluated by measuringleft ventricular pressure in absence or presence offollowing compounds; flutamide, prazosin, metoprolol andnifedipine. The results showed that dehydroisoandrosteronederivative significantly increased the perfusion pressure andcoronary resistance in comparison with the control conditionsand dehydroisoandrosterone. Additionally, other dataindicate that dehydroisoandrosterone derivative increase leftventricular pressure in a dose-dependent manner [1 9 10-9–1 9 10-4 mmol]; nevertheless, this phenomenon was significantlyinhibited by nifedipine at a dose of 1 9 10-6mmol. In conclusion, these data suggest that dehydroisoandrosteronederivative induces positive inotropic activitythrough of activation the L-type calcium channel.
SOME PROPERTIES OF EVOLUTION ALGEBRAS
Camacho, L.M.,Gomez, J.R.,Omirov, B.A.,Turdibaev, R.M. Korean Mathematical Society 2013 대한수학회보 Vol.50 No.5
The paper is devoted to the study of finite dimensional complex evolution algebras. The class of evolution algebras isomorphic to evolution algebras with Jordan form matrices is described. For finite dimensional complex evolution algebras the criterium of nilpotency is established in terms of the properties of corresponding matrices. Moreover, it is proved that for nilpotent $n$-dimensional complex evolution algebras the possible maximal nilpotency index is $1+2^{n-1}$.
Some properties of evolution algebras
L. M. Camacho,J. R. Gomez,B. A. Omirov,R. M. Turdibaev 대한수학회 2013 대한수학회보 Vol.50 No.5
The paper is devoted to the study of finite dimensional com- plex evolution algebras. The class of evolution algebras isomorphic to evolution algebras with Jordan form matrices is described. For finite dimensional complex evolution algebras the criterium of nilpotency is es- tablished in terms of the properties of corresponding matrices. Moreover, it is proved that for nilpotent n-dimensional complex evolution algebras the possible maximal nilpotency index is 1 + 2n−1.
Tribological performance of TiN and TiCN coatings on a working tool steel
M. T. Hernández-Sierra,L. D. Aguilera-Camacho,Arturo Ponce,J. S. García-Miranda,K. J. Moreno 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.8
Although the applications of TiN and TiCN coatings are extensive, their mechanical and tribological properties are influenced by the substrates in which they are deposited. The present work is focused on the tribological performance of TiN and TiCN coatings on a working tool steel. Besides, adhesion and microhardness tests were carried out. The adhesion performance of both coatings resulted in class 1, according to CEN/TS 1071-8 standard, which allows observing the quality of adhesion. The composite microhardness was investigated by the analysis of relative indentation (β). Pin-on-disk tests were performed in dry and lubricated condition at 100 °C against tungsten carbide (WC). Low friction coefficients of µ k = 0.08 for TiN and µ k = 0.03 for TiCN were obtained in lubricated conditions. Wear mechanisms were analyzed by scanning electron microscopy (SEM). Abrasive wear was observed as the principal wear mechanism in dry condition, while in lubricated conditions wear signals seem to be scarcely noticeable.
Simultaneous pulsatile flow and oscillating wall of a non-Newtonian liquid
E.E. Herrera-Valencia,M.L. Sánchez-Villavicencio,F. Calderas,M. Pérez-Camacho,L. Medina-Torres 한국유변학회 2016 Korea-Australia rheology journal Vol.28 No.4
In this work, analytical predictions of the rectilinear flow of a non-Newtonian liquid are given. The fluid is subjected to a combined flow: A pulsatile time-dependent pressure gradient and a random longitudinal vibration at the wall acting simultaneously. The fluctuating component of the combined pressure gradient and oscillating flow is assumed to be of small amplitude and can be adequately represented by a weakly stochastic process, for which a quasi-static perturbation solution scheme is suggested, in terms of a small parameter. This flow is analyzed with the Tanner constitutive equation model with the viscosity function represented by the Ellis model. According to the coupled Tanner-Ellis model, the flow enhancement can be separated in two contributions (pulsatile and oscillating mechanisms) and the power requirement is always positive and can be interpreted as the sum of a pulsatile, oscillating, and the coupled systems respectively. Both expressions depend on the amplitude of the oscillations, the perturbation parameter, the exponent of the Ellis model (associated to the shear thinning or thickening mechanisms), and the Reynolds and Deborah numbers. At small wall stress values, the flow enhancement is dominated by the axial wall oscillations whereas at high wall stress values, the system is governed by the pulsating noise perturbation. The flow transition is obtained for a critical shear stress which is a function of the Reynolds number, dimensionless frequency and the ratio of the two amplitudes associated with the pulsating and oscillating perturbations. In addition, the flow enhancement is compared with analytical and numerical predictions of the Reiner-Phillipoff and Carreau models. Finally, the flow enhancement and power requirement are predicted using biological rheometric data of blood with low cholesterol content.