Fluorogenic labeling of 5-formylpyrimidine nucleotides in DNA and RNA.

5-Formylcytosine (5fC) and 5-formyluracil (5fU) are natural nucleobase modifications that are generated by oxidative modification of 5-methylcytosine and thymine (or 5-methyluracil). Herein, we describe chemoselective labeling of 5-formylpyrimidine nucleotides in DNA and RNA by fluorogenic aldol-type condensation reactions with 2,3,3-trimethylindole derivatives. Mild and specific reaction conditions were developed for 5fU and 5fC to produce hemicyanine-like chromophores with distinct photophysical properties. Residue-specific detection was established by fluorescence readout as well as primer-extension assays. The reactions were optimized on DNA oligonucleotides and were equally suitable for the modification of 5fU- and 5fC-modified RNA. This direct labeling approach of 5-formylpyrimidines is expected to help in elucidating the occurrence, enzymatic transformations, and functional roles of these epigenetic/epitranscriptomic nucleobase modifications in DNA and RNA

Strange Stars with Realistic Quark Vector Interaction and Density-Dependent Scalar Potential

We derive an equation of state (EOS) for strange matter, starting from an interquark potential which (i) has asymptotic freedom built into it, (ii) shows confinement at zero density (rho(B)=0) and deconfinement at high rho(B), and (iii) gives a stable configuration for chargeless, beta-stable quark matter. This EOS is then used to calculate the structure of Strange Stars, and in particular their mass-radius relation. Our present results confirm and reinforce the recent claim [1,2] that the compact objects associated with the X-ray pulsar Her X-1, and with the X-ray burster 4U 1820-30 are strange stars

A batch-service queueing model with a discrete batch Markovian arrival process

Queueing systems with batch service have been investigated extensively during the past decades. However, nearly all the studied models share the common feature that an uncorrelated arrival process is considered, which is unrealistic in several real-life situations. In this paper, we study a discrete-time queueing model, with a server that only initiates service when the amount of customers in system (system content) reaches or exceeds a threshold. Correlation is taken into account by assuming a discrete batch Markovian arrival process (D-BMAP), i.e. the distribution of the number of customer arrivals per slot depends on a background state which is determined by a first-order Markov chain. We deduce the probability generating function of the system content at random slot marks and we examine the influence of correlation in the arrival process on the behavior of the system. We show that correlation merely has a small impact on the threshold that minimizes the mean system content. In addition, we demonstrate that correlation might have a significant influence on the system content and therefore has to be included in the model

Caloric curve in Au + Au collisions

Realistic caloric curves are obtained for $^{197}Au + ^{197}Au$ reaction with incident energy ranging from 35 to 130 MeV/nucleon in the dynamic statistical multifragmentation model. It is shown that for excitation energy 3 to 8 MeV/nucleon, the temperature remains constant in the range 5 to 6 MeV, which is close to experiment. The mechanism of energy deposition through the tripartition of colliding system envisaged in this model together with inter-fragment nuclear interaction are found to play important role. A possible signature of liquid-gas phase transition is seen in the specific heat distribution calculated from these caloric curves, and the critical temperature is found to be $\sim$ 6 to 6.5 MeV.Comment: Revtex, 10 pages, 4 postscipt figures, To appear in Phys. Rev. C (Rapid Communications

Josephson current in unconventional superconductors through an Anderson impurity

Josephson current for a system consisting of an Anderson impurity weakly coupled to two unconventional superconductors is studied and shown to be driven by a surface zero energy (mid-gap) bound-state. The repulsive Coulomb interaction in the dot can turn a $\pi$ junction into a 0-junction. This effect is more pronounced in p-wave superconductors while in high-temperature superconductors with $d_{x^2-y^2}$ symmetry it can exit for rather large artificial centers at which tunneling occurs within a finite region.Comment: 4 pages 3.eps figure

Reaction and proton-removal cross sections of 6^6Li, 7^7Be, 10^{10}B, 9,10,11^{9,10,11}C, ^{12N, 13,15^{13,15}O and 17^{17}Ne on Si at 15 to 53 MeV/nucleon

Excitation functions for total reaction cross sections, $\sigma_R$, were measured for the light, mainly proton-rich nuclei $^6$Li, $^7$Be, $^{10}$B, $^{9,10,11}$C, $^{12}$N, $^{13,15}$O, and $^{17}$Ne incident on a Si telescope at energies between 15 and 53 MeV/nucleon. The telescope served as target, energy degrader and detector. Proton-removal cross sections, $\sigma_{2p}$ for $^{17}$Ne and $\sigma_p$ for most of the other projectiles, were also measured. The strong absorption model reproduces the $A$-dependence of $\sigma_R$, but not the detailed structure. Glauber multiple scattering theory and the JLM folding model provided improved descriptions of the measured $\sigma_R$ values. $rms$ radii, extracted from the measured $\sigma_R$ using the optical limit of Glauber theory, are in good agreement with those obtained from high energy data. One-proton removal reactions are described using an extended Glauber model, incorporating second order noneikonal corrections, realistic single particle densities, and spectroscopic factors from shell model calculations.Comment: 16 pages, 6 figure