A Fast Optical Method for the Determination of Liquid Levels in Microplates
Parallel liquid handling systems are widely used in different applications of life sciences. In order to avoid false positive or negative results which lead to higher costs due to the replication of the experiments it is necessary to monitor the process and success of liquid delivery. An easy method for the determination of the liquid levels in microplates has been developed and evaluated. The optical method bases on the measurement of the liquid level using CCD cameras followed by special algorithms for the evaluation and visualization of the measured data. The proposed method was tested in changing environmental lighting for two different liquids. These tests confirm our approach towards optical liquid level determination for smallest volumes in microplates and also show the challenges regarding environmental lighting and different physical properties of fluids.
Camera grids for laboratory automation
This paper presents a straightforward method for mapping a multi-camera system to inspect multiple analytical samples carried in a microtiterplate, a labware standard used in life-science laboratories today. The high number of small samples that are provided by microplates burden difficulties when designing an inspection system with a single camera. The major concern is the perspective that is unique for every sample, and only a limited number of samples can be imaged in a favourable perspective, that is directly from below or above the sample. A way to overcome this problem is to use multiple cameras. This work presents the integration of an arbitrary number of cameras to support microplates of all types and densities. It provides a mapping framework to deliver the subimages to the inspection algorithms and includes a one-step registration procedure that uses a registration plate with microplate dimensions. Furthermore, an estimation of the system's mapping uncertainty is given.
The quantum particle in a box: what we can learn from classical electrodynamics
The problem of a charged particle enclosed in an infinite square potential well is analysed from the point of view of classical theory with the addition of the electromagnetic zero-point radiation field, with the aim to explore the extent to which such an analysis can contribute to enhance our understanding of the quantum behavior. First a proper treatment is made of the freely moving particle subject to the action of the radiation field, involving a frequency cutoff ωc. The jittering motion and the effective structure of the particle are sustained by the permanent action of the zero-point field. As a result, the particle interacts resonantly with the traveling field modes of frequency ωc in its proper frame of reference, which superpose to give rise to a modulated wave accompanying the particle. This is identified with the de Broglie wave, validating the choice of Compton’s frequency for ωc. For the stationary states of particles confined in the potential well, the Lorentz force produced by the accompanying field is shown to lead to discrete values for the mean speed and to an uneven probability distribution that echoes the corresponding quantum distribution. The relevance of the results obtained and the limitations of the classical approach used, are discussed in the context of present-day stochastic electrodynamics.