Relation between relaxation losses in domain-wall motion and ferromagnetic resonance in garnet films

Domain-wall mobility has been studied in garnet films having perpendicular magnetic anisotropy and a narrow FMR line. An analysis of the obtained and published experimental data shows that for the value of the Landau-Lifshits reduced damping parameter derived from FMR measurements, Λ_FMR>2.4×10⁻⁹ Oe²·s, the domain-wall mobility is inversely proportional to Λ_FMR, which is in agreement with classical theory. For Λ_FMR<2.43×10⁻⁹ Oe²·s, the mobility decreases with decreasing Λ_FMR. Possible reasons for this behavior are discussed. An empirical expression relating the losses entailed in domain motion to FMR-related losses for small Λ_FMR is proposed. Fiz. Tverd. Tela (St. Petersburg) 40, 1519–1525 (August 1998)     

Electro-elastic interactions and second order anisotropic constitutive equations

Piezoelectricity is usually expressed as an interaction between mechanical and electrical variables. The physics involved is hence governed by a coupling between Maxwell's equations of electromagnetism and the equations of elasticity. Such a coupling takes us through the piezoelectric constitutive relations. In this work, the second order anisotropic constitutive equations are treated, and in particular, the number of independent material constants is computed for all the 32 crystallographic classes.Paper presented, in reduced version, at the 12th Italian National Congress of Theoretical and Applied Mechanics (AIMETA '95), October 1995, Naples, Italy.     

Transition to Chaos in the Floating Half Zone Convection

The transition process from steady convection to chaos is experimentally studied in thermocapillary convections of floating half zone. The onset of temperature oscillations in the liquid bridge of floating half zone and further transitions of the temporal convective behaviour are detected by measuring the temperature in the liquid bridge. The fast Fourier transform reveals the frequency and amplitude characteristics of the flow transition. The experimental results indicate the existence of a sequence of period-doubling bifurcations that culminate in chaos. The measured Feigenbaum numbers are δ2 =4.69 and δ4 = 4.6, which are comparable with the theoretical asymptotic value δ=4.669.     

Compton effect in and power absorption by an electron gas

An analysis is made of Compton scattering by an electron gas. The power absorption and heating of an electron gas are calculated. The possible measurement of the intensity of intense coherent light beams is discussed.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 95–99, September, 1970.     

Design,synthesis of novel quinazolin-4-one derivatives and biological evaluation against human MCF-7 breast cancer cell line

A new series of 6,8-dibromo-2-(4-chlorophenyl)quinazolin-4(3H)-one derivatives VI–XIII were synthesized. Their chemical structures were confirmed by spectral and elemental analysis. The cytotoxic effect of the newly synthesized compounds was tested in vitro against human breast cancer cell line (MCF-7). Most of the tested compounds have shown promising cytotoxic activity. Compounds X and XIIIb exerted a powerful cytotoxic effect against MCF-7 with a very low IC50 (0.0015 and 0.0047 µmol/ml), while compounds VI, VII, VIII, XIIb, XI, XIIIc and IX exerted a moderate cytotoxic effect (IC50 0.01523, 0.0213, 0.031, 0.0478, 0.049, 0.068 and 0.079 µmol/ml respectively), compared to doxorubicin (0.0025 µmol/ml). Exploring their apoptotic effect; interestingly,all compounds activated apoptotic cascade in MCF-7. Compounds VI, XIIIb, XIIb, XI, XIIa, VII, V and VIII showed potent effect even much more than doxorubicin by 12.87–5.91 folds, while compounds XIIIc, IX, XIIIa, XIIc and X showed moderate increase in CASP3 activity by 4.96–3.22 folds relative to untreated cells more or less similar to doxorubicin (5.57 folds).     

Exact and Asymptotic Solutions for the Field of a Point Source in a Transversely Isotropic Medium

Exact and asymptotic solutions are obtained for the acoustic field generated by an isotropic pulsed point source in an infinite transversely isotropic elastic medium. The exact solution for the displacement field is obtained in the form of a double integral over the horizontal slowness and the frequency by using the method of integral transforms. The calculation of the integral over the horizontal slowness by the method of stationary phase reduces the exact solution to an asymptotic solution that is convenient for numerical calculations. Formulas are given for calculating the spreading factors and the wave fronts of quasi-longitudinal qP-waves and quasi-transverse qSV-waves. With the formulas obtained, the displacement field of a point source is investigated for a particular transversely isotropic medium.     

Ultra-low-frequency dust-electromagnetic modes in self-gravitating magnetized dusty plasmas

Obliquely propagating altra-low-frequency dust-electromagnetic waves in a self-gravitating, warm, magnetized, two fluid dusty plasma system have been investigated. Two special cases, namely, dust-Alfvén mode propagating parallel to the external magnetic field and dustmagnetosonic mode propagating perpendicular to the external magnetic field have also been considered. It has been shown that effects of self-gravitational field, dust fluid temperature, and obliqueness significantly modify the dispersion properties of these ultra-low-frequency dust-electromagnetic modes. It is also found that in parallel propagating dust-Alfvén mode these effects play no role, but in obliquely propagating dust-Alfvén mode or perpendicular propagating dust-magnetosonic mode the effect of self-gravitational field plays destabilizing role whereas the effect of dust/ion fluid temperature plays stabilizing role.