Efimov states in asymmetric systems

The conditions for occurrence of the Efimov effect is briefly described using hyperspherical coordinates. The strength of the effective hyperradial $\rho^{-2}$ potential appearing for two or three large scattering lengths is computed and discussed as function of two independent mass ratios of the three constituent particles. The effect is by far most pronounced for asymmetric systems with three very different masses. One Efimov state may by chance appear in nuclei. Many states could be present for systems with one electron and two neutral atoms or molecules. Estimates of the number of states and their sizes and energies are given.Comment: 7 pages, 3 figure

Low energy universality and scaling of Van der Waals forces

At long distances interactions between neutral ground state atoms can be described by the Van der Waals potential V(r) =-C6/r^6-C8/r^8 - ... . In the ultra-cold regime atom-atom scattering is dominated by s-waves phase shifts given by an effective range expansion p cot d0 (p) = -1/a0 + r0 p^2/2 + ... in terms of the scattering length a0 and the effective range r0. We show that while for these potentials the scattering length cannot be predicted, the effective range is given by the universal low energy theorem r0 = A + B/a0+ C/a0^2 where A,B and C depend on the dispersion coefficients Cn and the reduced di-atom mass. We confront this formula to about a hundred determinations of r0 and a0 and show why the result is dominated by the leading dispersion coefficient C6. Universality and scaling extends much beyond naive dimensional analysis estimates.Comment: 4 pages, 3 figure

СВЯЗЬ ЭФФЕКТИВНОСТИ ХИМИОТЕРАПИИ С ОСОБЕННОСТЯМИ ЭКСПРЕССИИ ТРАНСМЕМБРАННЫХ БЕЛКОВ P-ГЛИКОПРОТЕИНА (ABCB1), MRP2 (ABCC2), BCRP (ABCG2) У БОЛЬНЫХ ИНВАЗИВНЫМ РАКОМ МОЛОЧНОЙ ЖЕЛЕЗЫ

Overexpression of ABC drug transporters can cause multidrug resistance (MDR) in cancer cells, which is a major obstacle in the success of cancer chemotherapy. Our study revealed a correlation between the expression of invasive breast cancer resistance-associated proteins, such as P-glycoprotein (ABCB1), MRP2 (ABCC2), BCRP (ABCG2) in tumor cells and pathologic response to neoadjuvant chemotherapy. The response to neoadjuvant chemotherapy was shown to be associated with a lack of BCRP expression in tumor cells. The pathologic tumor response was correlated with the presence of positive MRP2 expression and the expression level of P-glycoprotein in cells of invasive breast cancer. Эффективность неоадъювантной химиотерапии при инвазивном раке молочной железы может быть снижена в связи с развитием феномена множественной лекарственной устойчивости, причиной которого в большинстве случаев является экспрессия трансмембранных белков семейства ABC-транспортеров. Выполненное исследование позволило выявить взаимосвязь между экспрессией в клетках опухоли инвазивного рака молочной железы белков лекарственной устойчивости семейства ABC-транспортеров: P-гликопротеина (ABCB1), MRP2 (ABCC2), BCRP (ABCG2), с эффективностью предоперационной химиотерапии и степенью лечебного патоморфоза опухолевой ткани. Было показано, что указанные параметры зависят от наличия мембранной экспрессии P-гликопротеина и степени выраженности его экспрессии опухолевыми клетками. Эффективность неоадъювантной химиотерапии сопряжена с отсутствием экспрессии BCRP в клетках опухоли. Степень лечебного патоморфоза в опухоли связана с наличием позитивной мембранной экспрессии MRP2, а также с уровнем мембранной экспрессии P-гликопротеина в клетках инвазивного рака молочной железы.

Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum