43 research outputs found
Expression of genes belonging to the IGF-system in glial tumors
The discrepancies arising from conflicting evidence on the results obtained by different laboratories in human gliomas are discussed. Our data highlight the importance of viewing the IGF-related proteins as a complex multifactorial system and show that changes in the expression levels of any one component of the system, in a given malignancy, should be interpreted with caution. As IGF targeting for anticancer therapy is rapidly becoming clinical reality, an understanding of this complexity is very timely.B cтaтьe oбсуждаются противоречивыe результаты, oпиcaнныe различными лабораториями для глиом. Пoлучeнныe данные демонстрируют важность рассмотрения белков семейства инсулиноподобных факторов роста как сложную мультифункциональную систему и показывают, что изменения в уровне экспрессии любого компонента системы в упомянутой опухоли должны интерпретироваться с предосторожностью. В связи с тем, что выбор членoв IGF-ceмeйcтвa в качестве мишени для противоопухолевой терапии быстро приобретает клиническую реальность, понимание сложноcти этой системы является весьма своевременным.У cтaттi oбговорюються суперечливi результати, опиcанi різними лабораторіями для гліом. Oтриманi дані демонструють важливість розгляду білків родини інсуліноподібних факторів росту як складну мультифункціональну систему і показують, що зміни рівня експресії будь-якого компонента системи у даній пухлині повинні інтерпретуватися із пересторогою. В зв’язку з тим, що вибір членiв IGF-ciмeйcтвa як мішені для протипухлинної терапії швидко набуває клінічної реальності, розуміння цієї системи є вельми своєчасним
Scattering of dipole-mode vector solitons: Theory and experiment
We study, both theoretically and experimentally, the scattering properties of
optical dipole-mode vector solitons - radially asymmetric composite
self-trapped optical beams. First, we analyze the soliton collisions in an
isotropic two-component model with a saturable nonlinearity and demonstrate
that in many cases the scattering dynamics of the dipole-mode solitons allows
us to classify them as ``molecules of light'' - extremely robust spatially
localized objects which survive a wide range of interactions and display many
properties of composite states with a rotational degree of freedom. Next, we
study the composite solitons in an anisotropic nonlinear model that describes
photorefractive nonlinearities, and also present a number of experimental
verifications of our analysis.Comment: 8 pages + 4 pages of figure
X-wave mediated instability of plane waves in Kerr media
Plane waves in Kerr media spontaneously generate paraxial X-waves (i.e.
non-dispersive and non-diffractive pulsed beams) that get amplified along
propagation. This effect can be considered a form of conical emission (i.e.
spatio-temporal modulational instability), and can be used as a key for the
interpretation of the out of axis energy emission in the splitting process of
focused pulses in normally dispersive materials. A new class of spatio-temporal
localized wave patterns is identified. X-waves instability, and nonlinear
X-waves, are also expected in periodical Bose condensed gases.Comment: 4 pages, 6 figure
Experimental control of steady state photorefractive self-focusing in InP:Fe at infrared wavelengths
Color Superconducting Phases of Cold Dense Quark Matter
We investigate color superconducting phases of cold quark matter at densities
relevant for the interiors of compact stars. At these densities, electrically
neutral and weak-equilibrated quark matter can have unequal numbers of up,
down, and strange quarks. The QCD interaction favors Cooper pairs that are
antisymmetric in color and in flavor, and a crystalline color superconducting
phase can occur which accommodates pairing between flavors with unequal number
densities. In the crystalline color superconductor, quarks of different flavor
form Cooper pairs with nonzero total momentum, yielding a condensate that
varies in space like a sum of plane waves. Rotational and translational
symmetry are spontaneously broken. We use a Ginzburg-Landau method to evaluate
candidate crystal structures and predict that the favored structure is
face-centered-cubic. We predict a robust crystalline phase with gaps comparable
in magnitude to those of the color-flavor-locked phase that occurs when the
flavor number densities are equal. Crystalline color superconductivity will be
a generic feature of the QCD phase diagram, occurring wherever quark matter
that is not color-flavor locked is to be found. If a very large flavor
asymmetry forbids even the crystalline state, single-flavor pairing will occur;
we investigate this and other spin-one color superconductors in a survey of
generic color, flavor, and spin pairing channels. Our predictions for the
crystalline phase may be tested in an ultracold gas of fermionic atoms, where a
similar crystalline superfluid state can occur. If a layer of crystalline quark
matter occurs inside of a compact star, it could pin rotational vortices,
leading to observable pulsar glitches.Comment: Ph.D. thesis, submitted to the MIT Department of Physics, May 2003.
Five chapters and two appendices (180 pages, 30 figures). Chapters 1 and 5
are new: chapter 1 is a detailed review of previous work, and chapter 5
discusses applications of the crystalline phase for the physics of pulsar
spin glitches and cold trapped atom