20 research outputs found
Dynamics of the Chiral Magnetic Effect in a weak magnetic field
We investigate the real-time dynamics of the chiral magnetic effect in
quantum electrodynamics (QED) and quantum chromodynamics (QCD). We consider a
field configuration of parallel (chromo)electric and (chromo)magnetic fields
with a weak perpendicular electromagnetic magnetic field. The chiral magnetic
effect induces an electromagnetic current along this perpendicular magnetic
field, which we will compute using linear response theory. We discuss specific
results for a homogeneous sudden switch-on and a pulsed (chromo)electric field
in a static and homogeneous (chromo)magnetic field. Our methodology can be
easily extended to more general situations. The results are useful for
investigating the chiral magnetic effect with heavy ion collisions and with
lasers that create strong electromagnetic fields. As a side result we obtain
the rate of chirality production for massive fermions in parallel electric and
magnetic fields that are static and homogeneous.Comment: 13 pages, 7 figures, revte
Studies of concentration and temperature dependencies of precipitation kinetics in iron-copper alloys using kinetic monte carlo and stochastic statistical simulations
The earlier-developed ab initio model and the kinetic Monte Carlo method
(KMCM) are used to simulate precipitation in a number of iron-copper alloys
with different copper concentrations x and temperatures T. The same simulations
are also made using the improved version of the earlier-suggested stochastic
statistical method (SSM). The results obtained enable us to make a number of
general conclusions about the dependencies of the decomposition kinetics in
Fe-Cu alloys on x and T. We also show that the SSM describes the precipitation
kinetics in a fair agreement with the KMCM, and employing the SSM in
conjunction with the KMCM enables us to extend the KMC simulations to the
longer evolution times. The results of simulations seem to agree with available
experimental data for Fe-Cu alloys within statistical errors of simulations and
the scatter of experimental results. Comparison of results of simulations to
experiments for some multicomponent Fe-Cu-based alloys enables us to make
certain conclusions about the influence of alloying elements in these alloys on
the precipitation kinetics at different stages of evolution.Comment: 18 pages, 17 postscript figures, LaTe
Real and virtual photons in an external constant electromagnetic field of most general form
The photon behavior in an arbitrary superposition of constant magnetic and
electric fields is considered on most general grounds basing on the first
principles like Lorentz- gauge- charge- and parity-invariance. We make model-
and approximation-independent, but still rather informative, statements about
the behavior that the requirement of causal propagation prescribes to massive
and massless branches of dispersion curves, and describe the way the eigenmodes
are polarized. We find, as a consequence of Hermiticity in the transparency
domain, that adding a smaller electric field to a strong magnetic field in
parallel to the latter causes enhancement of birefringence. We find the
magnetic field produced by a point electric charge far from it (a manifestation
of magneto-electric phenomenon). We establish degeneracies of the polarization
tensor that (under special kinematic conditions) occur due to space-time
symmetries of the vacuum left after the external field is imposed.Comment: 30 pages, 1 figure, 57 equations, reference list of 38 item
Theory of a quodon gas. With application to precipitation kinetics in solids under irradiation
Rate theory of the radiation-induced precipitation in solids is modified with
account of non-equilibrium fluctuations driven by the gas of lattice solitons
(a.k.a. quodons) produced by irradiation. According to quantitative
estimations, a steady-state density of the quodon gas under sufficiently
intense irradiation can be as high as the density of phonon gas. The quodon gas
may be a powerful driver of the chemical reaction rates under irradiation, the
strength of which exponentially increases with irradiation flux and may be
comparable with strength of the phonon gas that exponentially increases with
temperature. The modified rate theory is applied to modelling of copper
precipitation in FeCu binary alloys under electron irradiation. In contrast to
the classical rate theory, which disagrees strongly with experimental data on
all precipitation parameters, the modified rate theory describes quite well
both the evolution of precipitates and the matrix concentration of copper
measured by different methodsComment: V. Dubinko, R. Shapovalov, Theory of a quodon gas. With application
to precipitation kinetics in solids under irradiation. (Springer
International Publishing, Switzerland, 2014
Testing of CP, CPT and causality violation with the light propagation in vacuum in presence of the uniform electric and magnetic fields
We have considered the structure of the fundamental symmetry violating part
of the photon refractive index in vacuum in the presence of constant electric
and magnetic fields. This part of the refractive index can, in principle,
contain CPT symmetry breaking terms. Some of the terms violate Lorentz
invariance, whereas the others violate locality and causality. Estimates of
these effects, using laser experiments are considered.Comment: 12 page
КЛИНИЧЕСКИЙ СЛУЧАЙ УСПЕШНОГО ЛЕЧЕНИЯ ПОДРОСТКА С САРКОМОЙ ЮИНГА IV СТАДИИ
Background. Ewing’s sarcoma is one of the most common musculoskeletal cancers in children and adolescents. Extremely aggressive clinical course of Ewing’s sarcoma makes a successful treatment of this tumor difficult. Despite a comprehensive multidisciplinary approach to the treatment of this cancer, including chemotherapy, surgery and radiation therapy, rapid tumor progression, recurrence and resistance to chemotherapy are still common.Our purpose was to present the results of a personalized approach to multidisciplinary combination treatment for musculoskeletal cancer involving polychemotherapy, 3D conformal radiation therapy and modern surgical technologies.Description of the clinical case. A female patient presented to Rostov Research Institute of Oncology complaining of a tumor and moderate pain in soft tissues of the left iliac region, left lower extremity, and lameness when walking. After complete examination, the patient was diagnosed with Ewing’s sarcoma of the left ilium with lung metastases (Т3N0M1). The patient received 6 cycles of neoadjuvant chemotherapy according to EURO EWING 2008 protocol; tumor progression and lung metastasis were registered. Two cycles of second-line chemotherapy were performed; by the decision of the doctors’ council, the first stage of surgical treatment was performed: resection of the left ilium and the defect replacement with a temporary cement spacer. In the postoperative period, the patient underwent 8 cycles of adjuvant chemotherapy, external beam radiation therapy to the lungs (12 Gy total dose) and the primary tumor (46 iGy total dose), and 12 cycles of supporting therapy. A delayed second reconstructive stage of surgical treatment involved removal of a temporary cement spacer and implantation of an individual pelvic stability system. The patient was followed-up for 25 months after the combination treatment, had no complaints, and was able to ambulate without assistance; the motor function of the left hip joint was fully preserved. Conclusion. The use of non-standard high-technology approaches to surgical treatment of unfavorably localized Ewing’s Sarcoma in combination with chemo-radiation therapy allows patients with advanced tumors to achieve satisfactory results and good quality of life. Актуальность. Саркома Юинга занимает одно из лидирующих мест в онкологической патологии опорно-двигательной системы у детей и подростков. Успешное лечение затрудняет крайне агрессивное течение опухолевого процесса. Несмотря на мультидисциплинарный подход в лечении, включающий наряду с химиотерапевтическим и хирургическим методами лечения лучевую терапию, быстрая генерализация опухолевого процесса, рецидивы и резистентные к химиотерапии формы опухоли попрежнему часты.Целью работы явилось представление результатов персонифицированного подхода в комплексном мультидисциплинарном лечении злокачественной патологии опорно-двигательной системы с использованием многокомпонентной полихимиотерапии, 3D-конформной лучевой терапии и высоких хирургических технологий.Описание клинического случая. Больная обратилась в ФГБУ «РНИОИ» МЗ РФ в апреле 2016 г. с жалобами на наличие опухолевого образования и умеренных болей в мягких тканях левой подвздошной области, левой нижней конечности, хромоту при ходьбе. По данным обследования установлен диагноз: саркома Юинга левой подвздошной кости с метастазами в легкие, IV стадия (Т3N0M1). После 6 курсов неоадъювантной полихимиотерапии, согласно протоколу EWING 2008, отмечено прогрессирование опухоли с метастазами в легкие. Проведено 2 противорецидивных курса полихимиотерапии второй линии, решением консилиума врачей проведен первый этап хирургического лечения: резекция левой подвздошной кости с замещением дефекта временным цементным спейсером. В послеоперационном периоде больной проведено 8 курсов адъювантной полихимиотерапии, ДГТ на область обоих легких (СОД 12 Гр) и зону первичного очага (СОД 46 изоГР), 12 курсов поддерживающей терапии. Выполнен отсроченный реконструктивно-пластический этап хирургического лечения – удаление временного цементного спейсера с установкой индивидуальной тазовой стабилизирующей системы. Больная находится под наблюдением 25 мес после комплексного лечения, жалоб не предъявляет, передвигается самостоятельно, двигательная функция левого тазобедренного сустава сохранена в полном объеме.Заключение. Использование нестандартных высокотехнологичных подходов в хирургическом лечении саркомы Юинга неблагоприятных локализаций в сочетании с химиолучевой терапией позволяет достичь удовлетворительных результатов при лечении больных с распространенным опухолевым процессом и сохранения высокого уровня качества жизни.