On the log-product of the subtree-sizes of random trees

We determine the asymptotic behavior of the expected value and the variance of the log-product of the subtree-sizes of trees T_n belonging to simply generated families of rooted trees. © 1998 John Wiley & Sons, Inc. Random Struct. Alg., 12, 197–212, 1998     

Measuring the temperature of fluid in a micro-channel using thermochromic liquid crystals

Thermochromic liquid crystal (TLC) thermometry, which has been previously used at the macro-scale, is applied quantitatively in a microfluidic device for the first time. Much like the micro-scale version of the PIV technique, TLC thermometry implementation at the micro-scale must account for constraints on imaging and illumination configurations and the proximity of the measurements to interfaces and surfaces from which light scatters. Unlike ??PIV, TLC thermometry requires the use of white light, so unwanted reflections are managed using circular polarization filtering, which is implemented for the first time and may also have applications at the macro-scale. The validity and precision of the TLC thermometry technique are tested by imposing a linear temperature gradient along a micro-channel filled with stationary fluid. Additional work is required to develop the technique into a fully functional form and to realize the potential for use in various microfluidic applications including ??lab-on-a-chip?? devices, MEMS switches, inkjet printer nozzles, and for use with simultaneous velocity measurements.     

The role played by oxygen plasma on Teflon: relevance to the concept of "cryptoelectrons"

Dr Williams (AIP Adv., 2012, 2, 010701) suggested that cleaning Teflon by high pressure oxygen plasma may have affected our result that Cu(2+) and Pd(2+) ions can be absorbed but not chemically reduced by a Teflon surface rubbed by PMMA (Phys. Chem. Chem. Phys., 2012, 14, 5551). In response, we show that this treatment does not affect the adsorption of Cu(2+) and Pd(2+). We reaffirm our statement that Cu(2+) and Pd(2+) ions can be adsorbed by a Teflon surface only after rubbing with the organic polymers, not before rubbing.     

Electronic transport in graphene nanostructures on SiO2

We report two experiments on graphene nanostructures. The first was performed on a graphene nanoribbon, where the nature of electronic transport was investigated in detail. Electrons or holes are found to localize in pockets of the potential along the ribbon. Transport is governed by the joint action of localization and Coulomb interaction. The temperature-dependence of the conductance shows activated behavior at temperatures above a few Kelvin. The activation energy retraces the edges of Coulomb blockade diamonds found in nonlinear transport. In the second experiment the metallic tip of a low-temperature scanning force microscope was scanned above a graphene quantum dot. In addition to the familiar Coulomb blockade fringes, localized states are detected forming in the constrictions connecting the dot to source and drain.     

Laser excited S2 → S1 and S1 → S0 emission spectra and the S2 → Sn absorption spectrum of azulene in solution

We present the S₁ → S₀ fluorescence spectrum, between 740 and 940 nm, of azulene solutions (10^?3 M in methanol) excited with a Q-switched ruby laser. The nitrogen-laser excited S₂ → S₁ fluorescence spectrum, between 700 and 930 nm, is also reported. The transient S₁ → S_n spectrum between 500 and 650 nm was studied, using synchronous nitrogen laser and dye laser excitation. The S₅ (¹B₁(3)) state of azulene was found to be located at 45500 cm^?1 and the cross section σ₂₅ of the transient absorption S₂ → S₅ is estimated to be 3 × 10^?18 cm²/molecule.     

Application of machine learning to improve the results of high-throughput docking against the HIV-1 protease

We have previously reported that the application of a Laplacian-modified naive Bayesian (NB) classifier may be used to improve the ranking of known inhibitors from a random database of compounds after High-Throughput Docking (HTD). The method relies upon the frequency of substructural features among the active and inactive compounds from 2D fingerprint information of the compounds. Here we present an investigation of the role of extended connectivity fingerprints in training the NB classifier against HTD studies on the HIV-1 protease using three docking programs: Glide, FlexX, and GOLD. The results show that the performance of the NB classifier is due to the presence of a large number of features common to the set of known active compounds rather than a single structural or substructural scaffold. We demonstrate that the Laplacian-modified naive Bayesian classifier trained with data from high-throughput docking is superior at identifying active compounds from a target database in comparison to conventional two-dimensional substructure search methods alone.     

Immobilization of protein on aldehyde-containing gels—II. Activation of pyridine rings with cyanogen bromide

Cyanogen bromide was used to convert pyridine rings in polymers to polyaldehyde. By reaction with NH₂-containing substances, the rings are rebuilt, resulting in a pyridinium compound. Thus proteins and other NH₂-containing substances can be covalently bound. This method provides a new means for a immobilization technique. Pyridine-gels based on polysaccharide and polyacrylamide matrices, as well as pyridine glass beads, were synthesized and used to study the conditions necessary for coupling. Trypsin and — chymotrypsin were used as test substances for immobilization of proteins. Some properties of the bound protein were studied and compared to native enzyme. Some general results on the applicability of these gels for affinity chromatography are also presented.     

Analytic continuation by summation-methods

The paper deals with the analytic continuation of the geometric series by a family of linear transformations into some special domains of the complex plane.