Triply-Logarithmic Parallel Upper and Lower Bounds for Minimum and Range Minima over Small Domains

We consider the problem of computing the minimum ofnvalues, and several well-known generalizations [prefix minima, range minima, and all nearest smaller values (ANSV)] for input elements drawn from the integer domain [1···s], wheres ≥ n. In this article we give simple and efficient algorithms for all of the preceding problems. These algorithms all takeO(log log log s) time using an optimal number of processors andO(ns^ε) space (for constant ε < 1) on the COMMON CRCW PRAM. The best known upper bounds for the range minima and ANSV problems were previouslyO(log log n) (using algorithms for unbounded domains). For the prefix minima and for the minimum problems, the improvement is with regard to the model of computation. We also prove a lower bound of Ω(log log n) for domain sizes = 2^{Ω(log n log log n)}. Since, forsat the lower end of this range, log log n = Ω(log log log s), this demonstrates that any algorithm running ino(log log log s) time must restrict the range ofson which it works.     

Biased random walks

How much can an imperfect source of randomness affect an algorithm? We examine several simple questions of this type concerning the long-term behavior of a random walk on a finite graph. In our setup, at each step of the random walk a “controller” can, with a certain small probability, fix the next step, thus introducing a bias. We analyze the extent to which the bias can affect the limit behavior of the walk. The controller is assumed to associate a real, nonnegative, “benefit” with each state, and to strive to maximize the long-term expected benefit. We derive tight bounds on the maximum of this objective function over all controller's strategies, and present polynomial time algorithms for computing the optimal controller strategy.     

Lighting-up the dynamics of telomerization and DNA replication by CdSe-ZnS quantum dots

CdSe-ZnS core-shell quantum dots (QDs) act as photochemical centers for lighting-up the dynamics of telomerization or DNA replication.     

Decoherence in an anharmonic oscillator coupled to a thermal environment: a semiclassical forward-backward approach

The decoherence of an anharmonic oscillator in a thermal harmonic bath is examined via a semiclassical approach. A computational strategy is presented and exploited to calculate the time dependence of the purity and the decay of individual matrix elements in the energy representation for a variety of initial states. The time dependence of the decoherence is found to depend on the temperature of the bath, the coupling strength, the initial state of the oscillator, and the choice of quantity measuring the decoherence. Recurrences in the purity and in the off-diagonal matrix elements are observed, as well as the collapse of these matrix elements to the diagonal, providing evidence for the retention of quantum coherence for time scales longer than that indicated by the purity. The results are used to analyze the utility of the Caldeira-Leggett and Redfield models of decoherence and to assess the dependence of dephasing rates on the degree of structure in phase space. In several cases we find that the dephasing dynamics can be described as an initial Zeno-effect regime, followed by a Caldeira-Leggett region, followed by recurrences.     

Magneto-mechanical detection of nucleic acids and telomerase activity in cancer cells

The ultra-sensitive magneto-mechanical detection of DNA, single-base-mismatches in nucleic acids, and the assay of telomerase activity are accomplished by monitoring the magnetically induced deflection of a cantilever functionalized with magnetic beads associated with the biosensing interface. The analyzed M13phi DNA hybridized with the nucleic acid-functionalized magnetic beads is replicated in the presence of dNTPs that include biotin-labeled dUTP. The resulting beads are attached to an avidin-coated cantilever, and the modified cantilever is deflected by an external magnetic field. Similarly, telomerization of nucleic acid-modified magnetic beads in the presence of dNTPs, biotin-labeled dUTP, and telomerase from cancer cell extracts and the subsequent association of the magnetic beads to the cantilever surface results in the lever deflection by an external magnetic field. M13phi DNA is sensed with a sensitivity limit of 7.1 x 10(-20) M by the magneto-mechanical detection method.     

Electrocatalytic intercalator-induced winding of double-stranded DNA with polyaniline

The intercalation of doxorubicin into double-stranded DNA stimulates the electocatalyzed oxidation of aniline to polyaniline and its winding on the DNA template.     

Redox-active nucleic-acid replica for the amplified bioelectrocatalytic detection of viral DNA

A new concept for the amplified electrochemical detection of the 7229-base viral DNA of M13phi is developed. A thiolated 27-base nucleic acid (1) is assembled on an Au-electrode. Hybridization between the sensing interface and the M13phi DNA is followed by the polymerase-induced replication of the analyte DNA in the presence of dCTP, dGTP, dATP, and ferrocene-tethered-dUTP (2). The generated redox-active replica mediates electron transfer between the enzyme glucose oxidase (GOx) and the electrode and activates the bioelectrocatalyzed oxidation of glucose. The bioelectrocatalyzed oxidation of glucose provides a biocatalytic amplification path for the formation of the redox-active replica. The electrochemical techniques to follow the replication and the bioelectrocatalytic amplification are differential pulse voltammetry and cyclic voltammetry. The electrical responses from the system relate to the bulk concentration of the M13phi DNA, thus enabling the quantitative analysis of the viral gene.     

Evaluation of the initial growth of electroless deposited Co(W,P) diffusion barrier thin film for Cu metallization

The formation mechanism of electroless deposited Co(W,P) films is investigated. Co(W,P) films, containing 88-90 at% of Co and 10-12 at% of W and P, are deposited directly onto p-type Si(100) substrate via Pd wet activation. Co(W,P) initially nucleates around Pd activation sites and this is followed by a strong lateral growth. Uniform Co(W,P) thin films can be obtained after 2 min deposition. Fast immersion measurement shows that the mixed potential of Co(W,P) is −0.78 V versus Ag/AgCl electrode. XRD examination shows that the Pd layer has a domination of (111) texture and the principle microstructure of the as-deposited Co(W,P) film is the hcp phase of nano-sized ε-Co. The inelastic mean free path of diffused Cu in Co(W,P) is determined to be 7.37 Å which is significantly smaller than that (9.9 Å) in pure Co, indicating that Co(W,P) is a very effective barrier layer.     

Sequential intermediates in the base-catalyzed conversion of bis(pi-conjugated propargyl) sulfones to 1,3-dihydrobenzo- and naphtho[c]thiophene-2,2-dioxides

[reaction: see text] In a recent article, we reported on the base-catalyzed rearrangements of dipropargyl selenides, -sulfides, -sulfoxides, and -sulfones that eventually lead to polycyclic aromatic products. In the present work, we report on the first isolation and characterization of the thiophene dioxide intermediates 5b,c from a mild tandem isomerization/cyclization/aromatization of bis(pi-conjugated propargyl) sulfones. Monoallene 2b,c and diallene 3b intermediates were also identified by NMR. A kinetic study of the rearrangement of 1a-c revealed that the unusual facile tandem process is highly dependent on the nature of gamma-substitution.