TY - JOUR A1 - Dippong, Martin A1 - Carl, Peter A1 - Lenz, C. A1 - Schenk, J. A. A1 - Hoffmann, Katrin A1 - Schwaar, Timm A1 - Schneider, Rudolf A1 - Kuhne, Maren T1 - Hapten-specific single-cell selection of hybridoma clones by fluorescence-activated cell sorting for the generation of monoclonal antibodies N2 - The conventional hybridoma screening and subcloning process is generally considered to be one of the most critical steps in hapten-specific antibody production. It is time-consuming, monoclonality is not guaranteed, and the number of clones that can be screened is limited. Our approach employs a novel hapten-specific labeling technique of hybridoma cells. This allows for fluorescence-activated cell sorting (FACS) and single-cell deposition and thereby eliminates the above-mentioned problems. A two-step staining approach is used to detect antigen specificity and antibody expression: in order to detect antigen specificity, hybridoma cells are incubated with a hapten−horseradish peroxidase conjugate (hapten−HRP), which is subsequently incubated with a fluorophore-labeled polyclonal anti-peroxidase antibody (anti-HRP−Alexa Fluor 488). To characterize the expression of membrane-bound immunoglobulin G (IgG), a fluorophore-labeled anti-mouse IgG antibody (anti-IgG−Alexa Fluor 647) is used. Hundreds of labeled hybridoma cells producing monoclonal antibodies (mAbs) specific for a hapten were rapidly isolated and deposited from a fusion mixture as single-cell clones via FACS. Enzyme-linked immunosorbent assay (ELISA) measurements of the supernatants of the sorted hybridoma clones revealed that all hapten-specific hybridoma clones secrete antibodies against the target. There are significant improvements using this high-throughput technique for the generation of mAbs including increased yield of antibody-producing hybridoma clones, ensured monoclonality of sorted cells, and reduced development times. KW - Monoclonal antibodies KW - FACS KW - Hybridoma cells PY - 2017 DO - https://doi.org/10.1021/acs.analchem.6b04569 SN - 0003-2700 SN - 1520-6882 VL - 89 IS - 7 SP - 4007 EP - 4012 PB - ACS Publications AN - OPUS4-40320 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hoferer, J. A1 - Hoffmann, L.M. A1 - Goebbels, Jürgen A1 - Last, G. A1 - Weil, W. A1 - Kasper, G. T1 - Reconstruction algorithms for the internal packing density distribution of fibrous filter media based on tomographic data N2 - Algorithms were developed to approximate the 3-dimensional internal packing density distributions of fibrous filter media at different levels of detail and complexity. Each algorithm uses certain input information derived from X-ray tomographic data of filter samples. Algorithm 1 creates a binary media structure consisting of the true (i.e. tomographically determined) void distribution plus regions of uniform packing density. The average packing density of the media is maintained constant. Algorithm 2 creates a model fibrous structure of straight fibres of equal diameter and random length positioned randomly in space, while maintaining the true (i.e. tomographically determined) fibre orientation distribution. The number and length of the fibres on average adds up to the packing density of the filter. The model fibrous structure is recreated by a stationary Poisson process of convex bodies. Algorithm 3 distributes pores of random size and location within a homogeneous matrix, such that the average packing density again coincides with the true (i.e. tomographically determined) packing density. This algorithm is also based on a stationary Poisson process of convex bodies. The capability of each algorithm to recreate the essential structural features of the media was tested against 'reality' by computing the respective overall pressure drop of the filter as well as the velocity distribution in the filter interior, and comparing with the results obtained for the 'true' packing density distribution of a sample measured by tomography. Compared to the assumption of a completely homogenous filter (which gives roughly 2 times the actual Δp), all algorithms are closer to reality. The binary algorithm deviates in Δp by a factor of 1.8; algorithm 3 comes within a factor of 1.6 of the true Δp. The best approximation is by algorithm 2 which narrows the difference in Δp to a factor of 1.4. KW - X-ray tomography KW - Fibrous filter KW - Packing density PY - 2009 SN - 1479-0602 VL - 9 IS - 2 SP - 147 EP - 154 PB - Filtration Solutions CY - Newbold, Coleorton, Coalville AN - OPUS4-22880 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Voigt, J. A1 - Ebert, B. A1 - Hoffmann, Angelika A1 - Macdonald, R. T1 - Validierung eines "Fluorescent Enzyme Linked Immunosorbent Assay" (ELISA) N2 - Immunologische Verfahren haben während der vergangenen Jahrzehnte eine große Verbreitung in der Medizin gefunden. Grundlage dieser Verfahren ist die spezifische Bindung zwischen Antigen und Antikörper. Eine der wichtigsten Methoden zum sensitiven und quantitativen Nachweis biologisch relevanter Moleküle ist hierbei der Enzyme Linked Immunosorbent Assay (ELISA). Unter dem Aspekt der zahlreichen Einsatzgebiete ist die Frage nach Messunsicherheiten bei der Konzentrationsbestimmung von Biomolekülen mittels ELISA aus metrologischer Sicht von großem Interesse. Eine erhebliche Herausforderung stellt hierbei die Vielzahl von Einflussgrößen dar, die zudem hinsichtlich ihrer Messunsicherheit nur schwer zu quantifizieren sind. In Hinblick auf den Einsatz der Assays im Bereich der Laboratoriumsmedizin besteht die Notwendigkeit, Genauigkeit und Zuverlässigkeit dieser Messverfahren zu validieren. Zu diesem Zwecke wurden im Rahmen einer CCQM-Studie (CCQM- Comité consultatif pour la quantité de matiè re - métrologie en chimie ) internationale Vergleichsmessungen an einem ELISA zur Zytokinbestimmung (humanes Interferon-a) durchgeführt, an denen sich die PTB beteiligt hat. KW - ELISA KW - Interferon-Alpha KW - Metrologie KW - CCQM-Studie PY - 2008 SN - 0030-834X VL - 118 IS - 4 SP - 255 EP - 260 PB - Wirtschaftsverl. NW CY - Bremerhaven AN - OPUS4-22690 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Göbel, E. O. A1 - Hasche, K. A1 - Ulm, G. A1 - Krumrey, M. A1 - Ade, G. A1 - Stümpel, J. A1 - Herrmann, K. A1 - Koenders, L. A1 - Thomsen-Schmidt, P. A1 - Pohlenz, F. A1 - Xu, M. A1 - Dai, G. A1 - Hoffmann, K.-P. A1 - Busch, I. A1 - Frank, W. A1 - Procop, M. A1 - Beck, Uwe T1 - Kalibrierte Schichtdicken-Maßverkörperungen für Nanometerschichten, Teilvorhaben - Kalibrierung von Schichtdicken-Maßverkörperungen im Nanometerbereich - Abschlussbericht des BMBF Verbundvorhabens 13N7704 - 13N77041 KW - Schichtdicke KW - Nanometerbereich PY - 2003 UR - http://edok01.tib.uni-hannover.de/edoks/e01fb02/373214030.pdf SP - 1 EP - 131 PB - Physikalisch-Technische Bundesanstalt CY - Dresden AN - OPUS4-25428 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lenke, Karoline A1 - Schmidt, R. A1 - Märtin, J. A1 - Hoffmann, G. A1 - Cherif, C. T1 - Simulation of the yarn transportation dynamics in a warp knitting machine N2 - To date, in the textile manufacturing process of warp knitting, trouble-shooting and process optimization mainly rely on empirical knowledge and experiments. This factor limits the achievable increase in productivity and quality. On the other hand, using simulations, different phenomena that affect the quality of the knitted fabric and the knitting process can be clarified in the run-up of the experiments. Consequently, an increase in quality and flexibility can be reached with reduced experimental effort. This paper presents a process simulation of the warp thread dynamics in the thread feeding system of a warp knitting machine. For this purpose, a continuum model of the warp thread that includes the spatial dynamics of the thread and the axial transport movement has been developed. KW - Simulation of yarn transportation KW - Yarn transportation model KW - Warp knitting machine KW - Continuum model KW - Process optimization KW - Knitting PY - 2013 DO - https://doi.org/10.1177/0040517512470197 SN - 0040-5175 N1 - Geburtsname von Lenke, Karoline: Metzkes, K. - Birth name of Lenke, Karoline: Metzkes, K. VL - 83 IS - 12 SP - 1251 EP - 1262 PB - Sage Publ. CY - London AN - OPUS4-28381 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Marlow, Frank A1 - Dong, W. A1 - Hoffmann, Katrin A1 - Loerke, J. ED - Schüth, F. T1 - Optically and electronically functional materials PY - 2002 SN - 3-527-30246-8 SP - 3029 EP - 3063 PB - Wiley-VCH CY - Weinheim AN - OPUS4-1751 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weh, K. A1 - Noack, M. A1 - Hoffmann, Katrin A1 - Schröder, K.-P. A1 - Caro, J. T1 - Change of gas permeation by photoinduced switching of zeolite-azobenzene membranes of type MFI and FAU N2 - FAU membranes of type Na–X and MFI membranes of type silicalite-1 which contain adsorbed azobenzene (AZB), have photoswitchable permeation properties due to the trans–cis photoisomerization of AZB. The change of gas permeation through these host–guest composite membranes depends on the irradiation wavelength, the quality of the membranes and the amount of adsorbed AZB. The permeances of the gases in the trans-form of the zeolite-encapsulated AZB were higher than those in the cis-form. The separation factors of equimolar mixtures of N2/CO2 and CH4/CO2 fed through the FAU–AZB membrane were higher at trans-switching than at cis-switching. The changes of the permeances of single gases and of the separation factors of equimolar gas mixtures by photoinduced trans–cis switching were found to be reversible over numerous switching cycles. The experimental results are in agreement with predictions made by Monte Carlo simulations for passing of permeant gases through these host–guest systems with the zeolite-hosted AZB in the trans- and in the cis-configuration. PY - 2002 DO - https://doi.org/10.1016/S1387-1811(02)00331-1 SN - 1387-1811 SN - 1873-3093 VL - 54 IS - 1-2 SP - 15 EP - 26 PB - Elsevier CY - Amsterdam AN - OPUS4-1752 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fricke, F. A1 - Mahmood, S. A1 - Hoffmann, J. A1 - Brandalero, M. A1 - Liehr, Sascha A1 - Kern, Simon A1 - Meyer, Klas A1 - Kowarik, S. A1 - Westerdick, S. A1 - Maiwald, Michael A1 - Hübner, M. T1 - Artificial Intelligence for Mass Spectrometry and Nuclear Magnetic Resonance Spectroscopy N2 - Mass Spectrometry (MS) and Nuclear Magnetic Resonance Spectroscopy (NMR) are critical components of every industrial chemical process as they provide information on the concentrations of individual compounds and by-products. These processes are carried out manually and by a specialist, which takes a substantial amount of time and prevents their utilization for real-time closed-loop process control. This paper presents recent advances from two projects that use Artificial Neural Networks (ANNs) to address the challenges of automation and performance-efficient realizations of MS and NMR. In the first part, a complete toolchain has been developed to develop simulated spectra and train ANNs to identify compounds in MS. In the second part, a limited number of experimental NMR spectra have been augmented by simulated spectra to train an ANN with better prediction performance and speed than state-of-theart analysis. These results suggest that, in the context of the digital transformation of the process industry, we are now on the threshold of a possible strongly simplified use of MS and MRS and the accompanying data evaluation by machine-supported procedures, and can utilize both methods much wider for reaction and process monitoring or quality control. T2 - 2021 Design, Automation & Test in Europe Conference & Exhibition (DATE) CY - Grenoble, France DA - 01.02.2021 KW - Industry 4.0, KW - Cyber-physical systems KW - Artificial neural networks KW - Mass spectrometry KW - Nuclear magnetic resonance spectroscopy PY - 2021 DO - https://doi.org/10.23919/DATE51398.2021.9473958 SP - 615 EP - 620 PB - IEEE AN - OPUS4-55360 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fricke, F. A1 - Mahmood, S. A1 - Hoffmann, J. A1 - Brandalero, M. A1 - Liehr, Sascha A1 - Kern, Simon A1 - Meyer, Klas A1 - Kowarik, Stefan A1 - Westerdicky, S. A1 - Maiwald, Michael A1 - Hübner, M. T1 - Artificial Intelligence for Mass Spectrometry and Nuclear Magnetic Resonance Spectroscopy N2 - Mass Spectrometry (MS) and Nuclear Magnetic Resonance Spectroscopy (NMR) are critical components of every industrial chemical process as they provide information on the concentrations of individual compounds and by-products. These processes are carried out manually and by a specialist, which takes a substantial amount of time and prevents their utilization for real-time closed-loop process control. This paper presents recent advances from two projects that use Artificial Neural Networks (ANNs) to address the challenges of automation and performance-efficient realizations of MS and NMR. In the first part, a complete toolchain has been developed to develop simulated spectra and train ANNs to identify compounds in MS. In the second part, a limited number of experimental NMR spectra have been augmented by simulated spectra to train an ANN with better prediction performance and speed than state-of-theart analysis. These results suggest that, in the context of the digital transformation of the process industry, we are now on the threshold of a possible strongly simplified use of MS and MRS and the accompanying data evaluation by machine-supported procedures, and can utilize both methods much wider for reaction and process monitoring or quality control. T2 - 2021 Design, Automation & Test in Europe Conference & Exhibition (DATE) CY - Online meeting DA - 01.02.2021 KW - Industry 4.0 KW - Cyber-Physical Systems KW - Artificial Neural Networks KW - Mass Spectrometry KW - Nuclear Magnetic Resonance Spectroscopy PY - 2021 UR - www.date-conference.com SN - 978-3-9819263-5-4 SP - 615 EP - 620 PB - Research Publishing AN - OPUS4-52180 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Descalzo López, Ana Belén A1 - Rurack, Knut A1 - Weißhoff, Hardy A1 - Martínez-Mánez, Ramon A1 - Marcos, M. Dolores A1 - Amorós, P. A1 - Hoffmann, Katrin A1 - Soto, J. T1 - Rational Design of a Chromo- and Fluorogenic Hybrid Chemosensor Material for the Detection of Long-Chain Carboxylates N2 - A strategy for the rational design of a new optical sensor material for the selective recognition of long-chain carboxylates in water is presented. The approach relies on the combination of structure-property relationships to single out the optimal molecular sensor unit and the tuning of the sensing characteristics of an inorganic support material. A spacer-substituted 7-urea-phenoxazin-3-one was employed as the signaling moiety and a mesoporous trimethylsilylated UVM-7 (MCM-41 type) material served as the solid support. The sensor material shows the advantageous features of both modules that is absorption and emission in the visible spectral range, a fluorescence red-shift and enhancement upon analyte coordination, and the amplification of noncovalent (binding) and hydrogen-bonding (recognition) interactions in the detection event. Besides these basic results that are related to the design and performance of the sensor material, the paper discusses general aspects of amido-substituted phenoxazinone photophysics and addresses some general features of molecular anion recognition chemistry in aqueous vs nonaqueous media, utilizing steady-state and time-resolved optical as well as NMR spectroscopies. Detailed studies on potentially competing biochemical species and a first access to the schematic model of the response of the sensor material as obtained by a combination of fluorescence lifetime distribution analysis and Langmuir-type fitting of the gross binding constants complement the key issues of the paper. KW - Chemosensor KW - Carboxylate KW - Rationales Design KW - Hybridmaterialien KW - Fluoreszenz PY - 2005 DO - https://doi.org/10.1021/ja045683n SN - 0002-7863 SN - 1520-5126 VL - 127 SP - 184 EP - 200 PB - American Chemical Society CY - Washington, DC AN - OPUS4-5985 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -