Probing small molecule binding to amyloid fibrils

Much effort has focussed in recent years on probing the interactions of small molecules with amyloid fibrils and other protein aggregates. Understanding and control of such interactions are important for the development of diagnostic and therapeutic strategies in situations where protein aggregation is associated with disease. In this perspective article we give an overview over the toolbox of biophysical methods for the study of such amyloid-small molecule interactions. We discuss in detail two recently developed techniques within this framework: linear dichroism, a promising extension of the more traditional spectroscopic techniques, and biosensing methods, where surface-bound amyloid fibrils are exposed to solutions of small molecules. Both techniques rely on the measurement of physical properties that are very directly linked to the binding of small molecules to amyloid aggregates and therefore provide an attractive route to probe these important interactions.     

Characterization of quasi-arithmetic means without regularity condition

Acta Mathematica Hungarica - We show that bisymmetry, which is an algebraic property, has a regularity improving feature. More precisely, we prove that every bisymmetric, partially strictly...     

Preparative production of 5-desoxy-L-arabinose, xylitol and D-ribose from "diacetone glucose"]

Simple, reproducible preparative methods are described for the production of the title compounds from diacetone glucose.     

Non-dynamical stochastic resonance: Theory and experiments with white and various coloured noises

Summary We describe the simplest system which shows stochastic resonance. A linear(ized) theory for white and (almost) arbitrarily coloured noise is presented. The presented new system has new, unique properties which originate from itsnon-dynamical character; for example, the strength and phase shift of periodic response of the system is independent of the frequency. Experiments have been carried out with the following noise processes: (physical) white noise, (physical) Lorentzian noise and (physical) 1/f noise. With a small extension of the system, its linear-response regime can be significantly increased. As the system is similar to some simple models of neurones, the new results might have not only physical but also biological importance. Paper presented at the International Workshop “Fluctuations in Physics and Biology: Stochastic Resonance, Signal Processing and Related Phenomena”, Elba, 5–10 June 1994.     

An estimation of surface vibration excitation cross sections of CO,O and H adsorbed on tungsten

A simple model is described for the evaluation of adatom loss spectra of dipole vibrations perpendicular to the substrate. It considers the inelastic electron scattering before and after specular reflection on the substrate. By comparing the loss to elastic peak area the total cross section σ of the inelastic electron scattering can be estimated. The model was used for evaluating experimental results published in the literature by Ibach, Froitzheim, Adnot, Backx and Barnes on the systems WCO, WO and WH. The main results are: for the CO 258 meV loss peak, σ = (11.6?18.3)×10^?18cm²; for the O 78 meV loss peak, σ = (8.4?16.2) × 10^?18cm²; and for the H 130 and 155 meV loss peaks, σ =(0.73?2.2) × 10^?18cm². They are close to the theoretical values. A reasonable agreement was found between σ values determined on WO and WβCO (dissociated) systems.     

Multiphoton ionisation of different order from excited states of the He atoms in a glow-discharge

Multiphoton ionisation of different order was measured from the energy levels of the atoms He, excited in a low current glow discharge.     

Light intensity dependence of the multiphoton ionization probability in the resonance case

The general intensity dependence of the five-photon ionization probability of triplet metastable helium was measured.     

Calorimetric test of purity II

Dynamic and stepwise purity test techniques were compared, and it was established that in dynamic measurement the sample in many cases can not be considered to be in a state of equilibrium from the thermodynamic aspect. The problems of the measuring time and the accuracy of the results are discussed for the two-peak method, applicable for the processing of data obtained by the stepwise technique. It was established that the two-peak method can be improved. By using several peaks, the accuracy of the results and measuring time can be optimized.