The manufacturing of biochips by heating a multicomponent layer of polymeric microparticles that contain sensitive elements is simulated. Heating is performed up to the stage of polymer shell melting ...without damage to the sensitive elements. The corresponding thresholds of laser parameters (radiation power density) are detected. The preservation of biological complex functionality under these parameters is experimentally shown.
Image processing and pattern analysis can evaluate the deposition quality of triboelectrically charged microparticles on charged surfaces. The image processing method presented in this paper aims at ...controlling the quality of peptide arrays generated by particle based solid phase Merrifield combinatorial peptide synthesis. Incorrectly deposited particles are detected before the amino acids therein are coupled to the growing peptide. The calibration of the image acquisition is performed in a supervised training step in which all parameters of the quality analyzing algorithm are learnt given one representative image. Then, the correct deposition pattern is determined by a linear support vector machine. Knowing the pattern, contaminated areas can be detected by comparing the pattern with the actual deposition. Taking into account the resolution of the image acquisition system and its magnification factor, the number and size of contaminating particles can be calculated out of the number of connected foreground pixels.
Spatially selective deposition of electrically charged microparticles onto integrated circuits that generate electrical fields in programmable patterns using electrodes on their surface was ...previously limited to a pixel pitch of 100
μm. Now, we demonstrate spatially selective deposition onto pixels of 45
μm pitch in experiments on a test chip allowing arbitrary patterns, but being of limited size and of fixed characteristics, complemented by COMSOL simulations. Experiments on a prototype high voltage CMOS chip demonstrate the feasibility of miniaturisation in the first place, imply simulations of interest that cannot be tested experimentally and, conversely, complement the simplified simulation models by reality checks. Using COMSOL for the optimisation of the setup parameters, particles of decreasing average diameter in a number of aerosol and electrical field geometries are simulated with particular attention to minimising contamination (deposition of particles on undesirable locations). Combining these results, the average particle diameter is decreased from 10
μm to less than 3
μm and the deposition voltage is reduced from 100
V to 30
V, when using pixels with a pitch of 45
μm. Optimising these parameters allows for more than quadrupling the spot density compared to the previous chip, on which combinatorial particle deposition with minimal contamination is achieved. Peptide arrays, having been previously shown to be a major application for this method, benefit in particular, as the increase in density from 10,000
pixels/cm
2 to approximately 50,000
pixels/cm
2 promises a significant decrease in cost-per-peptide and amount of test specimens required.
Abstract
The Standard genetic code is the only reliable information about the first living cell on Earth called the last universal common ancestor —LUCA. The central mystery of the genetic code is ...the assignment of the canonical amino acids to the codons — base triplets. Simple and uniform combinatorial rules indicate that the standard genetic code arose during the fusion of four primordial single base-pair codes.
Vaccinations are among the most potent tools to fight infectious diseases. However, cross‐reactions are an ongoing problem and there is an urgent need to fully understand the mechanisms of the immune ...response. For the development of a methodological workflow, the linear epitopes in the immune response to the tetanus toxin is investigated in sera of 19 vaccinated Europeans applying epitope mapping with peptide arrays. The most prominent epitope, appearing in nine different sera (923IHLVNNESSEVIVHK937), is investigated in a substitution analysis to identify the amino acids that are crucial for the binding of the corresponding antibody species − the antibody fingerprint. The antibody fingerprints of different individuals are compared and found to be strongly conserved (929ExxEVIVxK937), which is astonishing considering the randomness of their development. Additionally, the corresponding antibody species is isolated from one serum with batch chromatography using the amino acid sequence of the identified epitope and the tetanus specificity of the isolated antibody is verified by ELISA. Studying antibody fingerprints with peptide arrays should be transferable to any kind of humoral immune response toward protein antigens. Furthermore, antibody fingerprints have shown to be highly disease‐specific and, therefore, can be employed as reliable biomarkers enabling the study of cross‐reacting antigens.
The vaccination against tetanus elicits a reliable protective immune response and, therefore, can serve as an ideal model system. In this study, the authors demonstrate the feasibility of a workflow for the detection of linear epitopes on the tetanus toxin with peptide microarrays in the resolution of single amino acids. With substitution analyses, the exact specificity of an identified antibody – the antibody fingerprint – is compared in different individuals and found to be highly conserved, which opens the exploitation of antibody fingerprints as reliable biomarkers, for the development of vaccines and the understanding of immune mechanisms.
Erfolgreicher Grenzgang Nesterov‐Müller, Alexander
Physik in unserer Zeit,
09/2016, Volume:
47, Issue:
5
Journal Article
Abstract
1859 bauten Robert Bunsen und Gustav Kirchhoff den ersten Spektrographen. Die Spektralanalyse revolutionierte viele Gebiete der Naturwissenschaften. Sie machte die Bestimmung von chemischen ...Elementen nicht nur auf der Erde, sondern im Licht von der Sonne und den Sternen möglich. Erst so wurde die chemische Zusammensetzung weit entfernter kosmischer Objekte der Analyse zugänglich. Die Entdeckung der Spektralanalyse ist ein zudem frühes Beispiel für eine erfolgreiche interdisziplinäre Forschung zwischen dem Chemiker Bunsen und dem Physiker Kirchhoff.
Erfolgreicher Grenzgang Nesterov‐Müller, Alexander
Physik in unserer Zeit,
September 2016, Volume:
47, Issue:
5
Journal Article
1859 bauten Robert Bunsen und Gustav Kirchhoff den ersten Spektrographen. Die Spektralanalyse revolutionierte viele Gebiete der Naturwissenschaften. Sie machte die Bestimmung von chemischen Elementen ...nicht nur auf der Erde, sondern im Licht von der Sonne und den Sternen möglich. Erst so wurde die chemische Zusammensetzung weit entfernter kosmischer Objekte der Analyse zugänglich. Die Entdeckung der Spektralanalyse ist ein zudem frühes Beispiel für eine erfolgreiche interdisziplinäre Forschung zwischen dem Chemiker Bunsen und dem Physiker Kirchhoff.
Recently, there is growing interest and need for dynamic pricing algorithms, especially, in the field of online marketplaces by offering smart pricing options for big online stores. We present an ...approach to adjust prices based on the observed online market data. The key idea is to characterize optimal prices as minimizers of a total expected revenue function, which turns out to be convex. We assume that consumers face information processing costs, hence, follow a discrete choice demand model, and suppliers are equipped with quantity adjustment costs. We prove the strong smoothness of the total expected revenue function by deriving the strong convexity modulus of its dual. Our gradient-based pricing schemes outbalance supply and demand at the convergence rates of \(\mathcal{O}(\frac{1}{t})\) and \(\mathcal{O}(\frac{1}{t^2})\), respectively. This suggests that the imperfect behavior of consumers and suppliers helps to stabilize the market.
We derive new prox-functions on the simplex from additive random utility models of discrete choice. They are convex conjugates of the corresponding surplus functions. In particular, we explicitly ...derive the convexity parameter of discrete choice prox-functions associated with generalized extreme value models, and specifically with generalized nested logit models. Incorporated into subgradient schemes, discrete choice prox-functions lead to natural probabilistic interpretations of the iteration steps. As illustration we discuss an economic application of discrete choice prox-functions in consumer theory. The dual averaging scheme from convex programming naturally adjusts demand within a consumption cycle.
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