Uptake of magnetic nanoparticles into cells for cell tracking

A challenge for future applications in nanotechnology is the functional integration of nano-sized materials into cellular structures. Here we investigated superparamagnetic Fe₃O₄ iron oxide nanoparticles coated with a lipid bilayer for uptake into cells and for targeting subcellular compartments. It was found that magnetic nanoparticles (MNPs) are effectively taken up into cells and make cells acquire magnetic activity. Biotin-conjugated MNPs were further functionalized by binding of the fluorescent tag streptavidin–fluorescein isothiocyanate (FITC) and, following uptake into cells, shown to confer magnetic activity and fluorescence labeling. Such FITC-MNPs were localized in the lysosomal compartment of cells which suggests a receptor-mediated uptake mechanism.     

High resolution laser spectroscopy of Ba Rydberg atoms

The purpose of the present paper is to illustrate some selected aspects of high resolution laser spectroscopy of Rydberg atoms, rather than giving an extensive review of the state of the art. The following topics will be discussed: (i) Excitation and detection of Ba Rydberg atoms with principal quantum numbers up ton≲300; (ii) Stark effect and atomic diamagnetism of high-n Ba Rydberg states in thel-mixing region, (iii) Resonance in singlet-triplet mixing of 6snp¹P₁ and 6snd¹D₂ Ba Rydberg states deduced from hyperfine structure measurements.     

Behavior of the surface of a bubbly liquid after detonation wave impact

In safety engineering, one position of interest inside heterogeneous systems of the type liquid–gas is the contact surface between these two phases. Under certain conditions, e.g. shock wave impact, phenomena can take place at this position that can have a significant influence on the explosion behavior of the system. In this work an investigation is presented about the existence of such phenomena on the surface of liquid cyclohexane with or without the existence of oxygen containing bubbles. The observations have been performed during the time before, as well as after, a detonation wave reflection on that surface. High-speed pressure and optical measurements have been applied. Apart from the experimental observations, also a theoretical analysis and discussion is presented in this contribution, which contains the comparison between calculated and experimental values.     

Über die Hydrolysegeschwindigkeit des Äthyläthers

Zusammenfassung Es wurde der hydrolytische Zerfall des Äthers in Alkohol unter dem Einfluß von Benzolsulfonsäure als Katalysator bei 98° gemessen. Die beobachtete Reaktion ist eine sauere Verseifung. Für die Minute als Zeiteinheit beträgt die Konstante dieser Verseifung ungefährk _s=9·10^–5 (98°)Die Analyse des Reaktionsgemisches wurde durch Veresterung des Alkohols zu Äthylacetat und Titration des letzteren vorgenommen.Die Kosten der vorliegenden Arbeit wurde zu einem Teil aus Mitteln bestritten, die ein Freund unseres Institutes zur Verfügung gestellt hat. Wir sagen ihm hiefür gemeinsam unseren Dank.     

Rayleigh–Benard convection in a chemical equilibrium gas (simulation of surface detonation wave initiation)

The problem of the Rayleigh–Benard convection for a chemical equilibrium gas is solved numerically. The gas is assumed to be incompressible, and the layer boundaries are assumed to be flat, isothermal, and free from shear stress. The Boussinesq model with the coefficient at the buoyancy term depending on the transverse coordinate is used. The resultant nonlinear system of equations is solved by a previously developed numerical method based on the spectral representation of vorticity and temperature fields. According to the idea of splitting, analytical formulas are first used to take into account the linear increase in disturbances, and then the nonlinear convective transfer is calculated by the finite-difference method. Various convection modes are obtained: stationary, periodic, quasi-periodic, and stochastic convection.     

Experimental study of magnetic forces on normal and null flux coil arrangements in the inductive levitation system

We report on measurements of lift and drag forces exerted by various small-scale current-carrying superconducting coils, placed near a large rotating disk. In detail we have studied the influences of shape and arrangement of the coils, as well as the influences of plate thickness, velocity and suspension height. In some experiments the drag force was measured under constant load condition. Most of the experimental results are compared with exact calculations based upon the general theory recently given by Miericke and Urankar [1] for infinitely wide but arbitrarily thick sheet tracks. The agreement between experiment and theory was generally good, and we believe that predictions for large-scale systems can be made with confidence.