Interrogation of MS/MS search data with an pI Filter algorithm to increase protein identification success

In high-throughput proteomics, the bottom-up approach has become a widely used method for the identification of proteins that is based on tryptic peptide MS/MS analysis. Separation methodologies that use IEF of tryptic peptides have recently been introduced and provide an extra dimension of peptide separation. In addition to its great fractionation capability, tryptic peptide prefractionation by IEF can also increase the protein identification success. The pI information of the peptide gained can be successfully used in a post-database search filtering step. We introduce a filtering algorithm that is based on the comparison of the experimental and theoretical pI's to validate peptide identifications by MS/MS data search engines.     

Parametric option pricing: A divide-and-conquer approach

Non-parametric option pricing models, such as artificial neural networks, are often found to outperform their parametric counterparts in empirical option pricing exercises. In this context, non-parametric models are viewed as more flexible and amenable to adaptive learning. However, the main drawback of non-parametric approaches is their lack of stability, which is detrimental to out-of-sample performance. This is the key reason why one may prefer a parsimonious parametric model. This paper proposes a parametric Takagi-Sugeno-Kang (TSK) fuzzy rule-based option pricing model that requires only a small number of rules to describe highly complex non-linear functions. The findings for this data-driven approach indicate that the TSK model presents a robust option pricing tool that is superior to an array of well-known parametric models from the literature. In addition, its predictive performance is consistently no worse than that of a non-parametric feedforward neural network model.     

Influence of Coupling Delay on Noise Induced Coherent Oscillations in Excitable Systems

Influence of small time-delays in coupling between noisy excitable systems on the coherence resonance and self-induced stochastic resonance is studied. Parameters of delayed coupled deterministic excitable units are chosen such that the system has only one attractor, namely the stationary state, for any value of the coupling and the time-lag. Addition of white noise induces qualitatively different types of coherent oscillations, and we analyzed the influence of coupling time-delay on the properties of these coherent oscillations. The main conclusion is that time-lag τ≥1, but still smaller than the refractory period, and sufficiently strong coupling drastically change signal to noise ratio in the quantitative and qualitative way. An interval of noise values implies quite large signal to noise ratio and different types of noise induced coherence are greatly enhanced. We also observed coincident spiking for small noise intensity and time-lag proportional to the inter-spike interval of the coherent spike trains. On the other hand, time-lags τ<1 and/or weak coupling induce negligible changes in the properties of the stochastic coherence.     

A geometric analysis of front propagation in a family of degenerate reaction-diffusion equations with cutoff

We investigate the effects of a Heaviside cutoff on the dynamics of traveling fronts in a family of scalar reaction-diffusion equations with degenerate polynomial potential that includes the classical Zeldovich equation. We prove the existence and uniqueness of front solutions in the presence of the cutoff, and we derive the leading-order asymptotics of the corresponding propagation speed in terms of the cutoff parameter. For the Zeldovich equation, an explicit solution to the equation without cutoff is known, which allows us to calculate higher-order terms in the resulting expansion for the front speed; in particular, we prove the occurrence of logarithmic (switchback) terms in that case. Our analysis relies on geometric methods from dynamical systems theory and, in particular, on the desingularization technique known as ‘blow-up.’     

TTF salts of optically pure cobalt pyridine amidates; detection of soluble assemblies with stoichiometry corresponding to the solid state

Optically pure anionic complexes of pyridinecarboxamide ligands, N(2),N(6)-bis((R)-α-methylbenzyl)pyridine-2, 6-dicarboxamide H(2)(R,R-L(1)) and N(2),N(6)-bis((S)-1-methoxypropan-2-yl)pyridine-2, 6-dicarboxamide H(2)(S,S-L(2)) have been synthesised and fully characterised. The complexes: (18-crown-6)K[Co(III)(R,R-L(1))(2)], (18-crown-6)K[Fe(III)(R,R-L(1))(2)] and K[Co(III)(S,S-L(2))(2)]·3H(2)O show interesting extended structures from 0D discrete units through 1D zigzag chains to 2D honeycomb layers. The complex anions were used in the synthesis of radical cation salts with tetrathiafulvalene (TTF). The salts (TTF)[Co(III)(R,R-L(1))(2)] and (TTF)[Co(III)(S,S-L(2))(2)]·EtOAc were characterised by single crystal X-ray diffraction and conductivity measurements. Both compounds comprise mono-oxidised TTF molecules and exhibit similar layered structures with no direct TTF stacking but in which phenyl substituents from the complex anion or co-crystallised ethyl acetate alternate with TTF(+) units. Solution spectroscopic and cyclic voltammetric evidence points to the formation of soluble assemblies between TTF(+) and the counterion which correspond to the stoichiometry observed by crystallography and other methods in the solid state.     

A partial proton transfer in hydrogen bond O-H···O in crystals of anhydrous potassium and rubidium complex chloranilates

Hydrogen bonding and proton transfer in the solid state are studied on the crystals of isostructural anhydrous potassium and rubidium complex chloranilates by variable-temperature single crystal X-ray diffraction, solid state (1)H NMR and IR spectroscopies, and periodic DFT calculations of equilibrium geometries, proton potentials, and NMR chemical shifts. Their crystal structures reveal neutral molecules of chloranilic acid and its dianions connected into a chain by O-H···O hydrogen bond. A strong hydrogen bond with a large-amplitude movement of the proton with NMR shift of 13-17 ppm and a broad continuum in IR spectra between 1000 and 500 cm(-1) were observed. Periodic DFT calculations suggest that proton transfer is energetically more favorable if it occurs within a single pair of chloranilate dianion and chloranilic acid molecule but not continuously along the chains of long periodicity. The calculated chemical shifts confirm the assumption that the weak resonance signals observed at lower magnetic fields pertain to the case when the proton migrates to the acceptor side of the hydrogen bond. The detected situation can be described by a partial proton transfer.     

Functionalized mesoporous silica nanoparticle-based visible light responsive controlled release delivery system

A supramolecular assembly for visible light responsive release of cargo molecules is presented. Sulforhodamine 101 was loaded inside the mesopores of mercaptopropyl-functionalized mesoporous silica nanoparticles (MP-MSN) and entrapped by mercaptopropyl-coordinated Ru(bpy)(2)(PPh(3))-moieties. Irradiation with visible light triggers the release of capping species and loaded molecules.     

Infrared optical constants, molar absorption coefficients, dielectric constants, molar polarisabilities, transition moments and dipole moment derivatives of liquid N,N-dimethylacetamide-carbon tetrachloride mixtures

Mid-infrared spectra of the DMA-carbon tetrachloride system by transmission and single- and multiple-reflection ATR technique in the whole composition range (0相似文献   

Evaluation of surface potential from single crystal electrode potential

The new method of evaluation of the point of zero potential for the metal oxide exhibiting a saddle-like surface potential function Ψ ₀(pH), as obtained by acid base potentiometric titration using Single Crystal Electrode, was proposed. The electrode potential of sapphire single crystal electrode (A crystal plane, $11\bar{2}0$ ) was measured, point of zero potential and surface potentials were evaluated, and the results were analyzed using the Surface Complexation Model. The electroneutrality point corresponding to the point of zero potential was found to be at pH_pzp=7.0. Thermodynamic protonation equilibrium constants for the first and the second step of protonation were obtained as $\lg K_{1}^{\circ} = 12.7$ ; $\lg K_{2}^{\circ} = 1.2$ .