Symmetry Induced 4-Wave Capillary Wave Turbulence

We report theoretical and experimental results on 4-wave capillary wave turbulence. A system consisting of two inmiscible and incompressible fluids of the same density can be written in a Hamiltonian way for the conjugated pair $(\eta,\Psi)$. When given the symmetry $z\to-z$, the set of weakly non-linear interacting waves display a Kolmogorov-Zakharov (KZ) spectrum $n_k\sim k^{-4}$ in wave vector space. The wave system was studied experimentally with two inmiscible fluids of almost equal densities (water and silicon oil) where the capillary surface waves are excited by a low frequency random forcing. The power spectral density (PSD) and probability density function (PDF) of the local wave amplitude are studied. Both theoretical and experimental results are in fairly good agreement with each other.Comment: 6 pages, 2 figure

Cellular redox state of patients with chronic b-lymphocytic leukemia after exposure to drugs

The redox state of cells of patients with chronic b-lymphocytic leukemia (B-CLL) was evaluated after exposure to drugs (fludarabel, vincristine, dexamethasone and imatinib) in therapeutic concentrations, and their sensitivity to these drugs was determined. The results indicate a decrease in the sensitivity of cells of B-CLL patients after a full course of chemotherapy to investigated drugs, compared with cells of patients before treatment. A change in the redox status in cells of B-CLL patients before treatment was established after exposure to drugs, compared with the group of patients after chemotherapy.Выполнена оценка редокс-состояния клеток пациентов схроническим B-лимфоцитарным лейкозом (B-ХЛЛ) после воздействия на них лекарственных средств (флударабела, винкристина, дексаметазона и иматиниба) в терапевтических концентрациях, а также определена их чувствительность к данным лекарственным средствам. Полученные результаты свидетельствуют о снижении чувствительности клеток пациентов с B-ХЛЛ, прошедших полный курс химиотерапии, к исследуемым лекарственным средствам, по сравнению с клетками пациентов, не прошедших химиотерапию. Установлено изменение редокс-статуса в клетках пациентов с B-ХЛЛ, не прошедших химиотерапию, после воздействия исследуемых лекарственных средств, по сравнению с группой пациентов после химиотерапии

Observation of dynamic maximum in a turbulent cascade on the surface of liquid hydrogen

We report on the experimental observation of energy accumulation near the high frequency boundary of the inertial range in the spectrum of turbulence in a system of capillary waves on the surface of liquid hydrogen driven by a harmonic force. The effect is manifested as a local maximum in the spectrum of pair correlation function of the surface elevation. This phenomenon is dynamical and can be seen only during reconfiguration of the turbulent cascade caused by waves generation of below the driving frequency

Classical capillary turbulence on the surface of quantum liquid He-II

Superfluid helium-4 is a unique liquid for experimental study of capillary wave turbulence due to its very low viscosity. We have studied the influence of amplitude and spectral characteristics of the excitation force on the behavior of the turbulent cascade of capillary waves in the cylindrical cell of diameter 30 mm. We have found that the experimental results can be explained within the framework of the wave turbulence theory (WTT) when the amplitude of pumping is relatively high. However, a very interesting phenomenon was observed at moderate amplitudes of harmonic surface excitation. It was detected the deviation of the turbulent spectrum from the power law function predicted by WTT at high frequencies — local maximum — that can be interpreted as wave energy accumulation. Our estimations show that the special case of wave turbulence is realized in our measurements, namely, discrete turbulence which is characterized by the strong influence of discreteness of cell resonant frequencies on the mechanism of the nonlinear interaction