TY - JOUR A1 - Palkopoulou, Eleftheria A1 - Lipson, Mark A1 - Mallick, Swapan A1 - Nielsen, Svend A1 - Rohland, Nadin A1 - Baleka, Sina Isabelle A1 - Karpinski, Emil A1 - Ivancevici, Atma M. A1 - Thu-Hien To, A1 - Kortschak, Daniel A1 - Raison, Joy M. A1 - Qu, Zhipeng A1 - Chin, Tat-Jun A1 - Alt, Kurt W. A1 - Claesson, Stefan A1 - Dalen, Love A1 - MacPhee, Ross D. E. A1 - Meller, Harald A1 - Rocar, Alfred L. A1 - Ryder, Oliver A. A1 - Heiman, David A1 - Young, Sarah A1 - Breen, Matthew A1 - Williams, Christina A1 - Aken, Bronwen L. A1 - Ruffier, Magali A1 - Karlsson, Elinor A1 - Johnson, Jeremy A1 - Di Palma, Federica A1 - Alfoldi, Jessica A1 - Adelsoni, David L. A1 - Mailund, Thomas A1 - Munch, Kasper A1 - Lindblad-Toh, Kerstin A1 - Hofreiter, Michael A1 - Poinar, Hendrik A1 - Reich, David T1 - A comprehensive genomic history of extinct and living elephants JF - Proceedings of the National Academy of Sciences of the United States of America KW - paleogenomics KW - elephantid evolution KW - mammoth KW - admixture KW - species divergence Y1 - 2018 U6 - https://doi.org/10.1073/pnas.1720554115 SN - 0027-8424 VL - 115 IS - 11 SP - E2566 EP - E2574 PB - National Acad. of Sciences CY - Washington ER - TY - JOUR A1 - Ruiz, Salome Vargas A1 - Hass, Roland A1 - Reich, Oliver T1 - Optical monitoring of milk fat phase transition within homogenized fresh milk by Photon Density Wave spectroscopy JF - International dairy journal N2 - Photon Density Wave (PDW) spectroscopy was applied for temperature dependent monitoring of melting and crystallization of milk fat within homogenized fresh milk. As an in-line process analytical technique, PDW spectroscopy quantifies continuously the optical properties of turbid material, providing an insight into its structural processes. Here, the measured absorption coefficients reflect temperature as well as fat content of milk and the reduced scattering coefficients probe physical changes of the light scattering fat droplets and casein micelles. Thermal processing reveals breakpoints within the temperature trend of the reduced scattering coefficient of fat containing milk. Found at 16 degrees C and 24 degrees C while cooling and heating, respectively, they are associated to the phase transitions of milk fat. Continuous isothermal measurement of the optical coefficients showed that the crystallization process requires several hours. The strongly changing reduced scattering coefficient implies that the thermal history of milk will have a major impact on any method based on light scattering as quantitative analytical technique. Y1 - 2012 U6 - https://doi.org/10.1016/j.idairyj.2012.03.012 SN - 0958-6946 VL - 26 IS - 2 SP - 120 EP - 126 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Bescherer, Klaus A1 - Munzke, Dorit A1 - Reich, Oliver A1 - Loock, Hans-Peter T1 - Fabrication and modeling of multimode fiber lenses JF - Applied optics N2 - We report on the fabrication, modeling, and experimental verification of the emission of fiber lenses fabricated on multimode fibers in different media. Concave fiber lenses with a radius of 150 mu m were fabricated onto a multimode silica fiber (100 mu m core) by grinding and polishing against a ruby sphere template. In our theoretical model we assume that the fiber guides light from a Lambertian light source and that the emission cone is governed solely by the range of permitted emission angles. We investigate concave and convex lenses at 532 nm with different radii and in a variety of surrounding media from air (n(0) = 1.00) to sapphire (n(0) = 1.77). It was found that noticeable focusing or defocusing effects of a silica fiber lens in ethanol (n(0) = 1.36) and dimethyl sulfoxide (DMSO) (n(0) = 1.48) are only observed when the fiber lens radius was less than the fiber diameter. Y1 - 2013 U6 - https://doi.org/10.1364/AO.52.000B40 SN - 1559-128X SN - 2155-3165 VL - 52 IS - 4 SP - B40 EP - B45 PB - Optical Society of America CY - Washington ER - TY - JOUR A1 - Schütt, Heiko Herbert A1 - Rothkegel, Lars Oliver Martin A1 - Trukenbrod, Hans Arne A1 - Reich, Sebastian A1 - Wichmann, Felix A. A1 - Engbert, Ralf T1 - Likelihood-based parameter estimation and comparison of dynamical cognitive models JF - Psychological Review N2 - Dynamical models of cognition play an increasingly important role in driving theoretical and experimental research in psychology. Therefore, parameter estimation, model analysis and comparison of dynamical models are of essential importance. In this article, we propose a maximum likelihood approach for model analysis in a fully dynamical framework that includes time-ordered experimental data. Our methods can be applied to dynamical models for the prediction of discrete behavior (e.g., movement onsets); in particular, we use a dynamical model of saccade generation in scene viewing as a case study for our approach. For this model, the likelihood function can be computed directly by numerical simulation, which enables more efficient parameter estimation including Bayesian inference to obtain reliable estimates and corresponding credible intervals. Using hierarchical models inference is even possible for individual observers. Furthermore, our likelihood approach can be used to compare different models. In our example, the dynamical framework is shown to outperform nondynamical statistical models. Additionally, the likelihood based evaluation differentiates model variants, which produced indistinguishable predictions on hitherto used statistics. Our results indicate that the likelihood approach is a promising framework for dynamical cognitive models. KW - likelihood KW - model fitting KW - dynamical model KW - eye movements KW - model comparison Y1 - 2017 U6 - https://doi.org/10.1037/rev0000068 SN - 0033-295X SN - 1939-1471 VL - 124 IS - 4 SP - 505 EP - 524 PB - American Psychological Association CY - Washington ER - TY - GEN A1 - Werner, Peter A1 - Münzberg, Marvin A1 - Hass, Roland A1 - Reich, Oliver T1 - Process analytical approaches for the coil-to-globule transition of poly(N-isopropylacrylamide) in a concentrated aqueous suspension T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - The coil-to-globule transition of poly(N-isopropylacrylamide) (PNIPAM) microgel particles suspended in water has been investigated in situ as a function of heating and cooling rate with four optical process analytical technologies (PAT), sensitive to structural changes of the polymer. Photon Density Wave (PDW) spectroscopy, Focused Beam Reflectance Measurements (FBRM), turbidity measurements, and Particle Vision Microscope (PVM) measurements are found to be powerful tools for the monitoring of the temperature-dependent transition of such thermo-responsive polymers. These in-line technologies allow for monitoring of either the reduced scattering coefficient and the absorption coefficient, the chord length distribution, the reflected intensities, or the relative backscatter index via in-process imaging, respectively. Varying heating and cooling rates result in rate-dependent lower critical solution temperatures (LCST), with different impact of cooling and heating. Particularly, the data obtained by PDW spectroscopy can be used to estimate the thermodynamic transition temperature of PNIPAM for infinitesimal heating or cooling rates. In addition, an inverse hysteresis and a reversible building of micrometer-sized agglomerates are observed for the PNIPAM transition process. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 944 KW - poly(N-isopropylacrylamide) KW - Photon Density Wave spectroscopy KW - Focused Beam Reflectance Measurement KW - turbidity measurement KW - Particle Vision Microscope measurement KW - rate-dependent lower critical solution temperature Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-431162 SN - 1866-8372 IS - 944 SP - 807 EP - 819 ER - TY - JOUR A1 - Andrews, N. L. P. A1 - Ferguson, T. A1 - Rangaswamy, A. M. M. A1 - Bernicky, A. R. A1 - Henning, N. A1 - Dudelzak, A. A1 - Reich, Oliver A1 - Barnes, Jack A. A1 - Loock, Hans-Peter T1 - Hadamard-Transform Fluorescence Excitation-Emission-Matrix Spectroscopy JF - Analytical chemistry N2 - We present a fluorescence excitation-emission-matrix spectrometer with superior data acquisition rates over previous instruments. Light from a white light emitting diode (LED) source is dispersed onto a digital micromirror array (DMA) and encoded using binary n-size Walsh functions ("barcodes"). The encoded excitation light is used to irradiate the liquid sample and its fluorescence is dispersed and detected using a conventional array spectrometer. After exposure to excitation light encoded in n different ways, the 2-dimensional excitation-emission-matrix (EEM) spectrum is obtained by inverse Hadamard transformation. Using this technique we examined the kinetics of the fluorescence of rhodamine B as a function of temperature and the acid-driven demetalation of chlorophyll into pheophytin-a. For these experiments, EEM spectra with 31 excitation channels and 2048 emission channels were recorded every 15 s. In total, data from over 3000 EEM spectra were included in this report. It is shown that the increase in data acquisition rate can be as high as [{n(n + 1)}/2]-fold over conventional EEM spectrometers. Spectral acquisition rates of more than two spectra per second were demonstrated. Y1 - 2017 U6 - https://doi.org/10.1021/acs.analchem.7b02400 SN - 0003-2700 SN - 1520-6882 VL - 89 SP - 8554 EP - 8564 PB - American Chemical Society CY - Washington ER - TY - CHAP A1 - Asche, Hartmut A1 - Böckmann, Christine A1 - Laue, Steffen A1 - Löhmannsröben, Hans-Gerd A1 - Lemke, Matthias A1 - Schober, Lars A1 - Reich, Oliver A1 - Lück, Erika A1 - Schütte, Marc A1 - Domsch, Horst A1 - Makower, Alexander A1 - Scheller, Frieder W. A1 - Stöcklein, Wolfgang A1 - Wollenberger, Ursula A1 - Schultze, Rainer A1 - Hengstermann, Theo A1 - Schael, Frank T1 - Umweltforschung für das Land Brandenburg : Projekt Umweltanalytik / Umweltmeßtechnik / Informationssysteme Y1 - 2000 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-3862 SP - 176 EP - 227 ER - TY - GEN A1 - Reich, Oliver A1 - Löhmannsröben, Hans-Gerd A1 - Schael, Frank T1 - Optical sensing with photon density waves: investigation of model media N2 - Investigations with frequency domain photon density waves allow elucidation of absorption and scattering properties of turbid media. The temporal and spatial propagation of intensity modulated light with frequencies up to more than 1 GHz can be described by the P1 approximation to the Boltzmann transport equation. In this study, we establish requirements for the appropriate choice of turbid model media and characterize mixtures of isosulfan blue as absorber and polystyrene beads as scatterer. For these model media, the independent determination of absorption and reduced scattering coefficients over large absorber and scatterer concentration ranges is demonstrated with a frequency domain photon density wave spectrometer employing intensity and phase measurements at various modulation frequencies. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 026 Y1 - 2003 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-13147 ER - TY - JOUR A1 - Sandmann, Michael A1 - Münzberg, Marvin A1 - Bressel, Lena A1 - Reich, Oliver A1 - Hass, Roland T1 - Inline monitoring of high cell density cultivation of Scenedesmus rubescens in a mesh ultra-thin layer photobioreactor by photon density wave spectroscopy JF - BMC Research Notes / Biomed Central N2 - Objective Due to multiple light scattering that occurs inside and between cells, quantitative optical spectroscopy in turbid biological suspensions is still a major challenge. This includes also optical inline determination of biomass in bioprocessing. Photon Density Wave (PDW) spectroscopy, a technique based on multiple light scattering, enables the independent and absolute determination of optical key parameters of concentrated cell suspensions, which allow to determine biomass during cultivation. Results A unique reactor type, called "mesh ultra-thin layer photobioreactor" was used to create a highly concentrated algal suspension. PDW spectroscopy measurements were carried out continuously in the reactor without any need of sampling or sample preparation, over 3 weeks, and with 10-min time resolution. Conventional dry matter content and coulter counter measurements have been employed as established offline reference analysis. The PBR allowed peak cell dry weight (CDW) of 33.4 g L-1. It is shown that the reduced scattering coefficient determined by PDW spectroscopy is strongly correlated with the biomass concentration in suspension and is thus suitable for process understanding. The reactor in combination with the fiber-optical measurement approach will lead to a better process management. KW - Photon density wave spectroscopy KW - Multiple light scattering KW - Process KW - analytical technology KW - Fiber-optical spectroscopy KW - Mesh ultra-thin layer KW - photobioreactor Y1 - 2022 U6 - https://doi.org/10.1186/s13104-022-05943-2 SN - 1756-0500 VL - 15 IS - 1 PB - Biomed Central (London) CY - London ER - TY - GEN A1 - Bressel, Lena A1 - Herzog, Bernd A1 - Reich, Oliver T1 - Monte-Carlo simulations of light transport in dense materials BT - dependent scattering and influence on sunscreen formulations T2 - Diffuse Optical Spectroscopy and Imaging N2 - Monte-Carlo calculations are carried out to simulate the light transport in dense materials. Focus lies on the calculation of diffuse light transmission through films of scattering and absorbing media considering additionally the effect of dependent scattering. Different influences like interaction type between particles, particle size, composition etc. can be studied by this program. Simulations in this study show major influences on the diffuse transmission. Further simulations are carried out to model a sunscreen film and study best compositions of this film and will be presented. KW - Monte-Carlo simulations KW - dependent scattering KW - sunscreen KW - light scattering KW - high concentrations Y1 - 2019 SN - 978-1-5106-2841-0 SN - 978-1-5106-2842-7 U6 - https://doi.org/10.1117/12.2527076 SN - 0277-786X SN - 1996-756X VL - 11074 PB - SPIE CY - Bellingham ER -