Characterization of time-resolved laser differential phase using 3D complementary cumulative distribution functions

An experimental method for characterizing the time-resolved phase noise of a fast switching tunable laser is discussed. The method experimentally determines a complementary cumulative distribution function of the laser's differential phase as a function of time after a switching event. A time resolved bit error rate of differential quadrature phase shift keying formatted data, calculated using the phase noise measurements, was fitted to an experimental time-resolved bit error rate measurement using a field programmable gate array, finding a good agreement between the time-resolved bit error rates.     

Linear collider test of a neutrinoless double beta decay mechanism in left–right symmetric theories

There are various diagrams leading to neutrinoless double beta decay in left?Cright symmetric theories based on the gauge group SU(2) _L ×SU(2) _R . All can in principle be tested at a linear collider running in electron?Celectron mode. We argue that the so-called ??-diagram is the most promising one. Taking the current limit on this diagram from double beta decay experiments, we evaluate the relevant cross section $e^{-} e^{-} \to W^{-}_{L} W^{-}_{R}$ , where $W^{-}_{L}$ is the Standard Model W-boson and $W^{-}_{R}$ the one from SU(2) _R . It is observable if the life-time of double beta decay and the mass of the W _R are close to current limits. Beam polarization effects and the high-energy behaviour of the cross section are also analyzed.     

Closed-form expression for Hankel determinants of the Narayana polynomials

We considered a Hankel transform evaluation of Narayana and shifted Narayana polynomials. Those polynomials arises from Narayana numbers and have many combinatorial properties. A mainly used tool for the evaluation is the method based on orthogonal polynomials. Furthermore, we provided a Hankel transform evaluation of the linear combination of two consecutive shifted Narayana polynomials, using the same method (based on orthogonal polynomials) and previously obtained moment representation of Narayana and shifted Narayana polynomials.     

Unusual entry to the novel 8-halo-N1-ribosyl hypoxanthine system by degradation of a cyclic adenosine-5'-diphosphate ribose analogue

Cyclic 8-bromo-inosine-5'-diphosphate ribose (8-Br-N1-cIDPR) was cleanly degraded at acidic pH by N9 ribosyl scission and subsequent pyrophosphate cleavage to give 8-bromo-N1-ribosyl hypoxanthine 5'-monophosphate (8-Br-N1-IMP), a novel class of mononucleotide, as the sole product.     

Synthesis of a [2]rotaxane through first- and second-sphere coordination

In an effort to expand the application of a new template from interpenetrated to interlocked molecular species, we report the synthesis of a new [2]rotaxane by means of both first- and second-sphere coordination of a palladium(II) dichloride subunit.     

Normal modes of redox-active tyrosine: conformation dependence and comparison to experiment

Redox-active tyrosine residues play important roles in long-distance electron reactions in enzymes such as prostaglandin H synthase, ribonucleotide reductase, and photosystem II (PSII). Spectroscopic characterization of tyrosyl radicals in these systems provides a powerful experimental probe into the role of the enzyme in mediation of long-range electron transfer processes. Interpretation of such data, however, relies critically on first establishing a spectroscopic fingerprint of isotopically labeled tyrosinate and tyrosyl radicals in nonenzymatic environments. In this report, FT-IR results obtained from tyrosinate, tyrosyl radical (produced by ultraviolet photolysis of polycrystalline tyrosinate), and their isotopologues at 77 K are presented. Assignment of peaks and isotope shifts is aided by density-functional B3LYP/6-311++G(3df,2p)//B3LYP/6-31++G(d,p) calculations of tyrosine and tyrosyl radical in several different charge and protonation states. In addition, characterization of the potential energy surfaces of tyrosinate and tyrosyl radical as a function of the backbone and ring torsion angles provides detailed insight into the sensitivity of the vibrational frequencies to conformational changes. These results provide a detailed spectroscopic interpretation, which will elucidate the structures of redox-active tyrosine residues in complex protein environments. Specific application of these data is made to enzymatic systems.     

High-order harmonic generation from ions in a capillary discharge

We demonstrate a significant extension of the high-order harmonic cutoff by using a fully-ionized capillary discharge plasma as the generation medium. The preionized plasma dramatically reduces ionization-induced defocusing and energy loss of the driving laser due to ionization. This allows for significantly higher photon energies, up to 150 eV, to be generated from xenon ions, compared with the 70 eV observed previously. We also demonstrate enhancement of the harmonic flux of nearly 2 orders of magnitude at photon energies around 90 eV when the capillary discharge is used to ionize xenon, compared with harmonic generation in a hollow waveguide. The use of a plasma as a medium for high-order harmonic generation shows great promise for extending efficient harmonic generation to much shorter wavelengths using ions.     

Investigations into the kinetics and thermodynamics of Sb(III) adsorption on goethite (alpha-FeOOH)

This study reports thermodynamic and kinetic data of Sb(III) adsorption from single metal solutions onto synthetic aqueous goethite (alpha-FeOOH). Batch equilibrium sorption experiments were carried out at 25 degrees C over a Sb:Fe molar range of 0.005-0.05 and using a goethite concentration of 0.44 g Fe/L. Experimental data were successfully modelled using Langmuir (R2 > or = 0.891) and Freundlich (R2 > or = 0.990) isotherms and the following parameters were derived from triplicate experiments: Kf = 1.903 +/- 0.030 mg/g and 1/n = 0.728 +/- 0.019 for the Freundlich model and b = 0.021 +/- 0.003 L/mg and Qmax = 61 +/- 8 mg/g for the Langmuir model. The thermodynamic parameters determined were the equilibrium constant, Keq =1.323 +/- 0.045, and the Gibb's free energy, DeltaG0 = -0.692 +/- 0.083 kJ/mol. The sorption process is very fast. At a Sb:Fe molar ratio of 0.05, 40-50% of the added Sb is adsorbed within 15 min and a steady state is achieved. The experimental data also suggest that desorption can occur within 24 h of reaction due to the oxidation of Sb(III) on the goethite surface. Finally, calculated pH of the aqueous solution using MINTEQ2 agrees well with the measured pH (3.9 +/- 0.7; n = 30). At pH 4, the dominant Sb species in solution are Sb(OH)3 and HSbO2 which both likely adsorb as inner sphere complexes to the positively charged goethite surface.