Multiparameter fluorescence image spectroscopy to study molecular interactions

Weidtkamp-Peters, Stefanie,Felekyan, Suren,Bleckmann, Andrea,Simon, Rudiger,Becker, Wolfgang,Kuhnemuth, Ralf,Seidel, Claus A.M. Korean Society of Photoscience 2009 Photochemical & photobiological sciences Vol.8 No.4

Multiparameter Fluorescence Image Spectroscopy (MFIS) is used to monitor simultaneously a variety of fluorescence parameters in confocal fluorescence microscopy. As the photons are registered one by one, MFIS allows for fully parallel recording of Fluorescence Correlation/Cross Correlation Spectroscopy (FCS/FCCS), fluorescence lifetime and pixel/image information over time periods of hours with picosecond accuracy. The analysis of the pixel fluorescence information in higher-dimensional histograms maximizes the selectivity of fluorescence microscopic methods. Moreover it facilitates a statistically-relevant data analysis of the pixel information which makes an efficient detection of heterogeneities possible. The reliability of MFIS has been demonstrated for molecular interaction studies in different complex environments: (I) detecting the heterogeneity of diffusion properties of the dye Rhodamine 110 in a sepharose bead, (II) F$\ddot{o}$rster Resonance Energy Transfer (FRET) studies in mammalian HEK293 cells, and (III) FRET study of the homodimerisation of the transcription factor BIM1 in plant cells. The multidimensional analysis of correlated changes of several parameters measured by FRET, FCS, fluorescence lifetime and anisotropy increases the robustness of the analysis significantly. The economic use of photon information allows one to keep the expression levels of fluorescent protein-fusion proteins as low as possible (down to the single-molecule level).

Operational modal analysis for Canton Tower

Yan Niu,Claus-Peter Fritzen,Peter Kraemer 국제구조공학회 2012 Smart Structures and Systems, An International Jou Vol.10 No.4

The 610 m high Canton Tower (formerly named Guangzhou New Television Tower) is currently considered as a benchmark problem for structural health monitoring (SHM) of high-rise slender structures. In the benchmark study task I, a set of 24-hour ambient vibration measurement data has been available for the output-only system identification study. In this paper, the vector autoregressive models (ARV) method is adopted in the operational modal analysis (OMA) for this TV tower. The identified natural frequencies, damping ratios and mode shapes are presented and compared with the available results from some other research groups which used different methods, e.g., the data-driven stochastic subspace identification (SSIDATA) method, the enhanced frequency domain decomposition (EFDD) algorithm, and an improved modal identification method based on NExT-ERA technique. Furthermore, the environmental effects on the estimated modal parameters are also discussed.

Impact identification and localization using a sample-force-dictionary - General Theory and its applications to beam structures

Ginsberg, Daniel,Fritzen, Claus-Peter Techno-Press 2016 Structural monitoring and maintenance Vol.3 No.3

Monitoring of impact loads is a very important technique in the field of structural health monitoring (SHM). However, in most cases it is not possible to measure impact events directly, so they need to be reconstructed. Impact load reconstruction refers to the problem of estimating an input to a dynamic system when the system output and the impulse response function are usually known. Generally this leads to a so called ill-posed inverse problem. It is reasonable to use prior knowledge of the force in order to develop more suitable reconstruction strategies and to increase accuracy. An impact event is characterized by a short time duration and a spatial concentration. Moreover the force time history of an impact has a specific shape, which also can be taken into account. In this contribution these properties of the external force are employed to create a sample-force-dictionary and thus to transform the ill-posed problem into a sparse recovery task. The sparse solution is acquired by solving a minimization problem known as basis pursuit denoising (BPDN). The reconstruction approach shown here is capable to estimate simultaneously the magnitude of the impact and the impact location, with a minimum number of accelerometers. The possibility of reconstructing the impact based on a noisy output signal is first demonstrated with simulated measurements of a simple beam structure. Then an experimental investigation of a real beam is performed.

Randomized Phase II Study of Ixabepilone or Paclitaxel Plus Carboplatin in Patients With Non–Small-Cell Lung Cancer Prospectively Stratified by Beta-3 Tubulin Status

Edelman, Martin J.,Schneider, Claus-Peter,Tsai, Chun-Ming,Kim, Heung-Tae,Quoix, Elisabeth,Luft, Alexander V.,Kaleta, Remigiusz,Mukhopadhyay, Pralay,Trifan, Ovidiu C.,Whitaker, Laura,Reck, Martin American Society for Clinical Oncology 2013 Journal of clinical oncology Vol.31 No.16

<P><B>Purpose</B></P><P>Retrospective studies have reported that tumor expression of the beta-3 tubulin (β3T) isoform is an unfavorable prognostic factor in non–small-cell lung cancer (NSCLC) treated with tubulin-inhibiting chemotherapy. Ixabepilone is a tubulin-inhibiting agent with low susceptibility to multiple resistance mechanisms including β3T isoform expression in several tumor models. This randomized phase II study evaluated ixabepilone-based chemotherapy in stage IIIb/IV NSCLC, compared with paclitaxel-based chemotherapy. Tumor specimens were prospectively evaluated for β3T expression.</P><P><B>Patients and Methods</B></P><P>Patients were stratified by β3T status (positive <I>v</I> negative) and randomly assigned at a ratio of 1:1 to receive ixabepilone (32 mg/m<SUP>2</SUP>) and carboplatin (area under concentration-time curve [AUC], 6) or paclitaxel (200 mg/m<SUP>2</SUP>) and carboplatin (AUC, 6) for up to six cycles. The primary end point was progression-free survival (PFS) in the β3T-positive subgroup.</P><P><B>Results</B></P><P>Ninety-five patients (β3T positive, 52; β3T negative, 43) received ixabepilone plus carboplatin; 96 patients (β3T positive, 49; β3T negative, 47) received paclitaxel plus carboplatin. No significant differences in median PFS were observed between arms for either subgroup (β3T positive, 4.3 months in both arms; β3T negative, 5.8 <I>v</I> 5.3 months). Ixabepilone did not significantly improve overall survival (OS) for the β3T-positive subset or the overall population. Adverse events were similar between the two arms and comparable with those in previous studies.</P><P><B>Conclusion</B></P><P>There was no predictive value of β3T in differentiating clinical activity of ixabepilone- or paclitaxel-containing regimens. Ixabepilone did not improve PFS or OS in patients with β3T-positive tumors. β3T-positive patients had worse PFS relative to β3T-negative patients, regardless of treatment; hence, β3T expression seems to be a negative prognostic factor, but not a predictive factor, in advanced NSCLC treated with either ixabepilone or paclitaxel platinum-based doublets.</P>

Operational modal analysis for Canton Tower

Niu, Yan,Kraemer, Peter,Fritzen, Claus-Peter Techno-Press 2012 Smart Structures and Systems, An International Jou Vol.10 No.4

The 610 m high Canton Tower (formerly named Guangzhou New Television Tower) is currently considered as a benchmark problem for structural health monitoring (SHM) of high-rise slender structures. In the benchmark study task I, a set of 24-hour ambient vibration measurement data has been available for the output-only system identification study. In this paper, the vector autoregressive models (ARV) method is adopted in the operational modal analysis (OMA) for this TV tower. The identified natural frequencies, damping ratios and mode shapes are presented and compared with the available results from some other research groups which used different methods, e.g., the data-driven stochastic subspace identification (SSI-DATA) method, the enhanced frequency domain decomposition (EFDD) algorithm, and an improved modal identification method based on NExT-ERA technique. Furthermore, the environmental effects on the estimated modal parameters are also discussed.

Sparsity-constrained Extended Kalman Filter concept for damage localization and identification in mechanical structures

Ginsberg, Daniel,Fritzen, Claus-Peter,Loffeld, Otmar Techno-Press 2018 Smart Structures and Systems, An International Jou Vol.21 No.6

Structural health monitoring (SHM) systems are necessary to achieve smart predictive maintenance and repair planning as well as they lead to a safe operation of mechanical structures. In the context of vibration-based SHM the measured structural responses are employed to draw conclusions about the structural integrity. This usually leads to a mathematically illposed inverse problem which needs regularization. The restriction of the solution set of this inverse problem by using prior information about the damage properties is advisable to obtain meaningful solutions. Compared to the undamaged state typically only a few local stiffness changes occur while the other areas remain unchanged. This change can be described by a sparse damage parameter vector. Such a sparse vector can be identified by employing $L_1$-regularization techniques. This paper presents a novel framework for damage parameter identification by combining sparse solution techniques with an Extended Kalman Filter. In order to ensure sparsity of the damage parameter vector the measurement equation is expanded by an additional nonlinear $L_1$-minimizing observation. This fictive measurement equation accomplishes stability of the Extended Kalman Filter and leads to a sparse estimation. For verification, a proof-of-concept example on a quadratic aluminum plate is presented.

Computational aspects of guided wave based damage localization algorithms in flat anisotropic structures

Jochen Moll,Miguel Angel Torres-Arredondo,Claus-Peter Fritzen 국제구조공학회 2012 Smart Structures and Systems, An International Jou Vol.10 No.3

Guided waves have shown a great potential for structural health monitoring (SHM) applications. In contrast to traditional non-destructive testing (NDT) methodologies, a key element of SHM approaches is the high process of automation. The monitoring system should decide autonomously whether the host structure is intact or not. A basic requirement for the realization of such a system is that the sensors are permanently installed on the host structure. Thus, baseline measurements become available that can be used for diagnostic purposes, i.e., damage detection, localization, etc. This paper contributes to guided wave-based inspection in anisotropic materials for SHM purposes. Therefore, computational strategies are described for both, the solution of the complex equations for wave propagation analysis in composite materials based on exact elasticity theory and the popular global matrix method, as well as the underlying equations of two active damage localization algorithms for anisotropic structures. The result of the global matrix method is an angular and frequency dependent wave velocity characteristic that is used subsequently in the localization procedures. Numerical simulations and experimental investigations through time-delay measurements are carried out in order to validate the proposed theoretical model. An exemplary case study including the calculation of dispersion curves and damage localization is conducted on an exemplary unidirectional composite structure where the ultrasonic signals processed in the localization step are simulated with the spectral element method. The proposed study demonstrates the capabilities of the proposed algorithms for accurate damage localization in anisotropic structures.

Computational aspects of guided wave based damage localization algorithms in flat anisotropic structures

Moll, Jochen,Torres-Arredondo, Miguel Angel,Fritzen, Claus-Peter Techno-Press 2012 Smart Structures and Systems, An International Jou Vol.10 No.3

Guided waves have shown a great potential for structural health monitoring (SHM) applications. In contrast to traditional non-destructive testing (NDT) methodologies, a key element of SHM approaches is the high process of automation. The monitoring system should decide autonomously whether the host structure is intact or not. A basic requirement for the realization of such a system is that the sensors are permanently installed on the host structure. Thus, baseline measurements become available that can be used for diagnostic purposes, i.e., damage detection, localization, etc. This paper contributes to guided wave-based inspection in anisotropic materials for SHM purposes. Therefore, computational strategies are described for both, the solution of the complex equations for wave propagation analysis in composite materials based on exact elasticity theory and the popular global matrix method, as well as the underlying equations of two active damage localization algorithms for anisotropic structures. The result of the global matrix method is an angular and frequency dependent wave velocity characteristic that is used subsequently in the localization procedures. Numerical simulations and experimental investigations through time-delay measurements are carried out in order to validate the proposed theoretical model. An exemplary case study including the calculation of dispersion curves and damage localization is conducted on an exemplary unidirectional composite structure where the ultrasonic signals processed in the localization step are simulated with the spectral element method. The proposed study demonstrates the capabilities of the proposed algorithms for accurate damage localization in anisotropic structures.

Differential Effects of Digoxin on Imiquimod-Induced Psoriasis-Like Skin Inflammation on the Ear and Back

( Marie Madsen ),( Tanja Xenia Pedersen ),( Lars Bo Nielsen ),( Claus Johansen ),( Peter Riis Hansen ) 대한피부과학회 2018 Annals of Dermatology Vol.30 No.4