Approximation to the mean curve in the LCS problem

The problem of sequence comparison via optimal alignments occurs naturally in many areas of applications. The simplest such technique is based on evaluating a score given by the length of a longest common subsequence divided by the average length of the original sequences. In this paper we investigate the expected value of this score when the input sequences are random and their length tends to infinity. The corresponding limit exists but is not known precisely. We derive a theoretical large deviation, convex analysis and Monte Carlo based method to compute a consistent sequence of upper bounds on the unknown limit. An empirical practical version of our method produces promising numerical results.     

Die Adsorptionstheorie der geschichteten Niederschläge

Ohne Zusammenfassung     

Towards detection and identification of circulating tumour cells using Raman spectroscopy

Body fluids are easily accessible and contain valuable indices for medical diagnosis. Fascinating tools are tumour cells circulating in the peripheral blood of cancer patients. As these cells are extremely rare, they constitute a challenge for clinical diagnostics. In this contribution we present the Raman spectroscopic-based identification of different single cells in suspension that are found in peripheral blood of cancer patients including healthy cells like leukocytes and erythrocytes, and tumour cells like leukaemic cells and cells originating from solid tumours. Leukocytes and erythrocytes were isolated from the peripheral blood of healthy donors while myeloid leukaemia cells (OCI-AML3) and breast carcinoma derived cells (MCF-7, BT-20) were obtained from cell cultures. A laser emitting 785 nm light was used for optical trapping the single cells in the laser focus and to excite the Raman spectrum. Support vector machines were applied to develop a supervised classification model with spectra of 1210 cells originating from three different donors and three independent cultivation batches. Distinguishing tumour cells from healthy cells was achieved with a sensitivity of >99.7% and a specificity of >99.5%. In addition, the correct cell types were predicted with an accuracy of approximately 92%.     

Probing Ag nanoparticle surface oxidation in contact with (in)organics: an X‐ray scattering and fluorescence yield approach

Characterizing interfacial reactions is a crucial part of understanding the behavior of nanoparticles in nature and for unlocking their functional potential. Here, an advanced nanostructure characterization approach to study the corrosion processes of silver nanoparticles (Ag‐Nps), currently the most highly produced nanoparticle for nanotechnology, is presented. Corrosion of Ag‐Nps under aqueous conditions, in particular in the presence of organic matter and halide species common to many natural environments, is of particular importance because the release of toxic Ag⁺ from oxidation/dissolution of Ag‐Nps may strongly impact ecosystems. In this context, Ag‐Nps capped with polyvinolpyrrolidone (PVP) in contact with a simple proxy of organic matter in natural waters [polyacrylic acid (PAA) and Cl^? in solution] has been investigated. A combination of synchrotron‐based X‐ray standing‐wave fluorescence yield‐ and X‐ray diffraction‐based experiments on a sample consisting of an approximately single‐particle layer of Ag‐Nps deposited on a silicon substrate and coated by a thin film of PAA containing Cl revealed the formation of a stable AgCl corrosion product despite the presence of potential surface stabilizers (PVP and PAA). Diffusion and precipitation processes at the Ag‐Nps–PAA interface were characterized with a high spatial resolution using this new approach.     

Strongly regular graphs with non-trivial automorphisms

The possible existence of 16 parameter sets for strongly regular graphs with 100 or less vertices is still unknown. In this paper, we outline a method to search for strongly regular graphs by assuming a non-trivial automorphism of prime order. Among these unknown parameter sets, we eliminated many possible automorphisms, but some small prime orders still remain. We also found 6 new strongly regular graphs with parameters (49,18,7,6).     

On quasi-symmetric 2-(28,12,11) and 2-(36,16,12) designs

New quasi-symmetric 2-(28,12,11) and 2-(36,16,12) designs are constructed by embedding known designs into symmetric designs.Partially supported by an NSA Research Grant.     

NN correlations in a multinucleon system

Cross sections for processes involving three or more identical nucleons in the final state are expected to be strongly suppressed near the threshold because of the Pauli exclusion principle. It is shown that the Migdal-Watson effect (final-state interaction between nucleons) removes this suppression.     

Natural-convection heat transfer in a nonuniform finite annulus with concentric heat source

In this paper, the mechanisms of natural-convection heat transfer inside a nonuniform finite annulus have been numerically investigated. The system is actually a streamlined, water-filled latex balloon with a coaxial cylindrical heating element. The balloon can be applied as a local hyperthermia treatment device for the removal of undesirable tissue if sufficiently high temperatures and preferably uniform surface heat fluxes can be maintained. A validated control-volume-based method has been employed to solve the coupled transient three-dimensional transport equations for laminar free convection. The effects of heat-source temperature distributions and device orientations on the heat transfer have been studied. Possible design improvements of this device are discussed.