Shell to shell energy transfer in MHD, Part II: Kinematic dynamo

We study the transfer of energy between different scales for forced three-dimensional MHD turbulent flows in the kinematic dynamo regime. Two different forces are examined: a non-helical Taylor Green flow with magnetic Prandtl number P_M=0.4, and a helical ABC flow with P_M=1. This analysis allows us to examine which scales of the velocity flow are responsible for dynamo action, and identify which scales of the magnetic field receive energy directly from the velocity field and which scales receive magnetic energy through the cascade of the magnetic field from large to small scales. Our results show that the turbulent velocity fluctuations are responsible for the magnetic field amplification in the small scales (small scale dynamo) while the large scale field is amplified mostly due to the large scale flow. A direct cascade of the magnetic field energy from large to small scales is also present and is a complementary mechanism for the increase of the magnetic field in the small scales. Input of energy from the velocity field in the small magnetic scales dominates over the energy that is cascaded down from the large scales until the large-scale peak of the magnetic energy spectrum is reached. At even smaller scales, most of the magnetic energy input is from the cascading process.Comment: Submitted to PR

Numerical solutions of the three-dimensional magnetohydrodynamic alpha-model

We present direct numerical simulations and alpha-model simulations of four familiar three-dimensional magnetohydrodynamic (MHD) turbulence effects: selective decay, dynamic alignment, inverse cascade of magnetic helicity, and the helical dynamo effect. The MHD alpha-model is shown to capture the long-wavelength spectra in all these problems, allowing for a significant reduction of computer time and memory at the same kinetic and magnetic Reynolds numbers. In the helical dynamo, not only does the alpha-model correctly reproduce the growth rate of magnetic energy during the kinematic regime, but it also captures the nonlinear saturation level and the late generation of a large scale magnetic field by the helical turbulence.Comment: 12 pages, 19 figure

Результаты лечения рабдомиосаркомы мочеполовой системы у детей. Собственный 15-летний опыт

Background. Despite significount successes in treatment of rhabdomyosarcoma of urogenital system in children there are unresolved questions of choise of optimal chemotherapys combinations, intensity of chemotherapy, volumes and terms of radiotherapy, tactics of treatment residual tumors in last 3 decades.The objective: show 15 years experience of treatment local and locally prevalent rhabdomyosarcoma urogenital system in children. The prognosis for children and adolescents with rhabdomyosarcoma has improved with refinements in multi-modal therapy.Materials and methods. In reseach are included 86 patients with a median age of 8.4 (0.7–17) with a local genitourinary rhabdomyosarcoma, treated in N.N. Blokhin National Medical Research Centre of Oncology from 2000 to 2016. All patients were treated in different riskadopted clinical protocol included chemotherapy and radiotherapy (IRS, SIOP, CWS and local protocol DORMS-6).Results. A 10-year overall survival and disease-free survival rates were 76 and 72 % in the entire group rhabdomyosarcoma patients, respectively.Conclusion. The effectiveness of the risk-adopted strategy in the genitourinary rhabdomyosarcoma treatment as well as the need of new approaches and in the cases of residual viable tumor after induction chemotherapy was demonstrated. Введение. Несмотря на существенные успехи в лечении рабдомиосаркомы мочеполовой системы у детей, в последние 3 десятилетия нерешенными остаются вопросы выбора оптимальных комбинаций химиопрепаратов, интенсивности химиотерапии, объемов и сроков проведения лучевой терапии, тактики в отношении резидуальных опухолей.Цель исследования – представить 15‑летний опыт лечения локализованной и местно-распространенной рабдомиосаркомы мочеполовой системы у детей.Материалы и методы. В исследование включены 86 пациентов (средний возраст 8,4 года (0,7–17 лет)) с эмбриональной рабдомиосаркомой мочеполовой системы, получавших лечение в НМИЦ онкологии им. Н. Н. Блохина в период с 2000 по 2016 г. Лечение проводили согласно риск-адаптированным клиническим протоколам (IRS, SIOP, CWS-10, ДОРМС-6) на базе критериев TNM, IRSG и COG.Результаты. Десятилетняя общая выживаемость и безрецидивная выживаемость в общей группе составила 76 и 72 % соответственно. Заключение. Показаны эффективность риск-адаптированной терапии рабдомиосаркомы мочеполовой системы у детей, необходимость поиска новых подходов для пациентов с нерадикально удаленными и резидуальными опухолями

The results of treatment of urogenital system rhabdomyosarcoma in children. 15-years of experience

Background. Despite significount successes in treatment of rhabdomyosarcoma of urogenital system in children there are unresolved questions of choise of optimal chemotherapys combinations, intensity of chemotherapy, volumes and terms of radiotherapy, tactics of treatment residual tumors in last 3 decades.The objective: show 15 years experience of treatment local and locally prevalent rhabdomyosarcoma urogenital system in children. The prognosis for children and adolescents with rhabdomyosarcoma has improved with refinements in multi-modal therapy.Materials and methods. In reseach are included 86 patients with a median age of 8.4 (0.7–17) with a local genitourinary rhabdomyosarcoma, treated in N.N. Blokhin National Medical Research Centre of Oncology from 2000 to 2016. All patients were treated in different riskadopted clinical protocol included chemotherapy and radiotherapy (IRS, SIOP, CWS and local protocol DORMS-6).Results. A 10-year overall survival and disease-free survival rates were 76 and 72 % in the entire group rhabdomyosarcoma patients, respectively.Conclusion. The effectiveness of the risk-adopted strategy in the genitourinary rhabdomyosarcoma treatment as well as the need of new approaches and in the cases of residual viable tumor after induction chemotherapy was demonstrated