Complementary addressed modification of oligonucleotide d(pGpGpCpGpGpA) with platinum derivative of oligonucleotide d(pTpCpCpGpCpCpTpTpT)

AbstractNew heterobifunctional reagent [BrPt(dien)—(CH2)6—(dien)Pt(H2O)]3+ (I) (− dien = diethylenetriamine residue) is proposed for preparation of complementary addressed reagents, reactive derivatives of oligonucleotides and polynucleotides. Two reactive groupings of (I) bind to oligonucleotides at different rates due to the higher reactivity of −[(dien)Pt(H2O)]2+ as compared to −[(dien)Pt Br]+. Using (I), bromodiethylenetriaminoplatinum group was attached to the oligonucleotide d(pTpCpCpGpCpCpTpTpT) (II) by rapid reaction of aquatriaminoplatinum group of (I) with guanosine residue of (II). The reactive oligonucleotide derivative III thus obtained was shown to modify predominantly 5′-terminal guanosine residue in the complementary oligonucleotide d(pGpGpCpGpGpA) (IV)

Vacuum creation of quarks at the time scale of QGP thermalization and strangeness enhancement in heavy-ion collisions

The vacuum parton creation in quickly varying external fields is studied at the time scale of order 1 fm/$c$ typical for the quark-gluon plasma formation and thermalization. To describe the pre-equilibrium evolution of the system the transport kinetic equation is employed. It is shown that the dynamics of production process at times comparable with particle inverse masses can deviate considerably from that based on classical Schwinger-like estimates for homogeneous and constant fields. One of the effects caused by non-stationary chromoelectric fields is the enhancement of the yield of $s\bar{s}$ quark pairs. Dependence of this effect on the shape and duration of the field pulse is studied together with the influence of string fusion and reduction of quark masses.Comment: REVTEX, 11pp. incl. 4 figures, to be published in Phys. Lett.

Vacuum fluctuations and topological Casimir effect in Friedmann-Robertson-Walker cosmologies with compact dimensions

We investigate the Wightman function, the vacuum expectation values of the field squared and the energy-momentum tensor for a massless scalar field with general curvature coupling parameter in spatially flat Friedmann-Robertson-Walker universes with an arbitrary number of toroidally compactified dimensions. The topological parts in the expectation values are explicitly extracted and in this way the renormalization is reduced to that for the model with trivial topology. In the limit when the comoving lengths of the compact dimensions are very short compared to the Hubble length, the topological parts coincide with those for a conformal coupling and they are related to the corresponding quantities in the flat spacetime by standard conformal transformation. In the opposite limit of large comoving lengths of the compact dimensions, in dependence of the curvature coupling parameter, two regimes are realized with monotonic or oscillatory behavior of the vacuum expectation values. In the monotonic regime and for nonconformally and nonminimally coupled fields the vacuum stresses are isotropic and the equation of state for the topological parts in the energy density and pressures is of barotropic type. In the oscillatory regime, the amplitude of the oscillations for the topological part in the expectation value of the field squared can be either decreasing or increasing with time, whereas for the energy-momentum tensor the oscillations are damping.Comment: 20 pages, 2 figure