@article{KnoedlerRuehlEmontsetal.2019,
  author    = {Kn{\"o}dler, Matthias and R{\"u}hl, Clemens and Emonts, Jessica and Buyel, Johannes Felix},
  title     = {Seasonal weather changes affect the yield and quality of recombinant proteins produced in transgenic tobacco plants in a greenhouse setting},
  series = {Frontiers in Plant Science},
  journal   = {Frontiers in Plant Science},
  number    = {10},
  publisher = {Frontiers Media},
  address   = {Lausanne},
  issn      = {1664-462X (online-ressource)},
  doi       = {10.3389/fpls.2019.01245},
  pages     = {13 Seiten},
  year      = {2019},
  abstract  = {Transgenic plants have the potential to produce recombinant proteins on an agricultural scale, with yields of several tons per year. The cost-effectiveness of transgenic plants increases if simple cultivation facilities such as greenhouses can be used for production. In such a setting, we expressed a novel affinity ligand based on the fluorescent protein DsRed, which we used as a carrier for the linear epitope ELDKWA from the HIV-neutralizing antibody 2F5. The DsRed-2F5-epitope (DFE) fusion protein was produced in 12 consecutive batches of transgenic tobacco (Nicotiana tabacum) plants over the course of 2 years and was purified using a combination of blanching and immobilized metal-ion affinity chromatography (IMAC). The average purity after IMAC was 57 ± 26\% (n = 24) in terms of total soluble protein, but the average yield of pure DFE (12 mg kg-1) showed substantial variation (± 97 mg kg-1, n = 24) which correlated with seasonal changes. Specifically, we found that temperature peaks (>28°C) and intense illuminance (>45 klx h-1) were associated with lower DFE yields after purification, reflecting the loss of the epitope-containing C-terminus in up to 90\% of the product. Whereas the weather factors were of limited use to predict product yields of individual harvests conducted for each batch (spaced by 1 week), the average batch yields were well approximated by simple linear regression models using two independent variables for prediction (illuminance and plant age). Interestingly, accumulation levels determined by fluorescence analysis were not affected by weather conditions but positively correlated with plant age, suggesting that the product was still expressed at high levels, but the extreme conditions affected its stability, albeit still preserving the fluorophore function. The efficient production of intact recombinant proteins in plants may therefore require adequate climate control and shading in greenhouses or even cultivation in fully controlled indoor farms.},
  language  = {en}
}
@phdthesis{Emonts2013,
  author    = {Emonts, Jessica},
  title     = {Searching for many defective edges in hypergraphs},
  publisher = {Rheinisch-Westf{\"a}lischen Technischen Hochschule Aachen},
  address   = {Aachen},
  pages     = {VIII, 104 Seiten : Ill.},
  year      = {2013},
  language  = {en}
}
@article{BernauKnoedlerEmontsetal.2022,
  author    = {Bernau, C. R. and Kn{\"o}dler, Matthias and Emonts, Jessica and J{\"a}pel, Ronald Colin and Buyel, Johannes Felix},
  title     = {The use of predictive models to develop chromatography-based purification processes},
  series = {Frontiers in Bioengineering and Biotechnology},
  journal   = {Frontiers in Bioengineering and Biotechnology},
  number    = {10},
  publisher = {Frontiers Media},
  address   = {Lausanne},
  issn      = {2296-4185 (online-ressource)},
  doi       = {10.3389/fbioe.2022.1009102},
  pages     = {25 Seiten},
  year      = {2022},
  abstract  = {Chromatography is the workhorse of biopharmaceutical downstream processing because it can selectively enrich a target product while removing impurities from complex feed streams. This is achieved by exploiting differences in molecular properties, such as size, charge and hydrophobicity (alone or in different combinations). Accordingly, many parameters must be tested during process development in order to maximize product purity and recovery, including resin and ligand types, conductivity, pH, gradient profiles, and the sequence of separation operations. The number of possible experimental conditions quickly becomes unmanageable. Although the range of suitable conditions can be narrowed based on experience, the time and cost of the work remain high even when using high-throughput laboratory automation. In contrast, chromatography modeling using inexpensive, parallelized computer hardware can provide expert knowledge, predicting conditions that achieve high purity and efficient recovery. The prediction of suitable conditions in silico reduces the number of empirical tests required and provides in-depth process understanding, which is recommended by regulatory authorities. In this article, we discuss the benefits and specific challenges of chromatography modeling. We describe the experimental characterization of chromatography devices and settings prior to modeling, such as the determination of column porosity. We also consider the challenges that must be overcome when models are set up and calibrated, including the cross-validation and verification of data-driven and hybrid (combined data-driven and mechanistic) models. This review will therefore support researchers intending to establish a chromatography modeling workflow in their laboratory.},
  language  = {en}
}
@article{EmontsBuyel2023,
  author    = {Emonts, Jessica and Buyel, Johannes Felix},
  title     = {An overview of descriptors to capture protein properties - Tools and perspectives in the context of QSAR modeling},
  series = {Computational and Structural Biotechnology Journal},
  journal   = {Computational and Structural Biotechnology Journal},
  number    = {21},
  publisher = {Research Network of Computational and Structural Biotechnology},
  address   = {Gotenburg},
  issn      = {2001-0370 (online-ressource)},
  doi       = {10.1016/j.csbj.2023.05.022},
  pages     = {3234 -- 3247},
  year      = {2023},
  abstract  = {Proteins are important ingredients in food and feed, they are the active components of many pharmaceutical products, and they are necessary, in the form of enzymes, for the success of many technical processes. However, production can be challenging, especially when using heterologous host cells such as bacteria to express and assemble recombinant mammalian proteins. The manufacturability of proteins can be hindered by low solubility, a tendency to aggregate, or inefficient purification. Tools such as in silico protein engineering and models that predict separation criteria can overcome these issues but usually require the complex shape and surface properties of proteins to be represented by a small number of quantitative numeric values known as descriptors, as similarly used to capture the features of small molecules. Here, we review the current status of protein descriptors, especially for application in quantitative structure activity relationship (QSAR) models. First, we describe the complexity of proteins and the properties that descriptors must accommodate. Then we introduce descriptors of shape and surface properties that quantify the global and local features of proteins. Finally, we highlight the current limitations of protein descriptors and propose strategies for the derivation of novel protein descriptors that are more informative.},
  language  = {en}
}
@book{Heuermann2024,
  author    = {Heuermann, Holger},
  title     = {Microwave technology: field simulation, non-linear circuit technology, components and subsystems, plasma technology, antennas and propagation},
  publisher = {Springer},
  address   = {Wiesbaden},
  isbn      = {978-3-658-45685-6},
  doi       = {10.1007/978-3-658-45686-3},
  pages     = {XII, 391 Seiten},
  year      = {2024},
  abstract  = {The book covers various numerical field simulation methods, nonlinear circuit technology and its MF-S- and X-parameters, as well as state-of-the-art power amplifier techniques. It also describes newly presented oscillators and the emerging field of GHz plasma technology. Furthermore, it addresses aspects such as waveguides, mixers, phase-locked loops, antennas, and propagation effects, in combination with the bachelor's book 'High-Frequency Engineering,' encompassing all aspects related to the current state of GHz technology.},
  language  = {en}
}
@misc{BrotsackPettrak2014,
  author    = {Brotsack, Raimund and Pettrak, J{\"u}rgen},
  title     = {Mikrobiologische Biomethan-Erzeugung mit Wasserstoff aus der thermischen Vergasung von kohlenstoffhaltigen Einsatzstoffen},
  year      = {2014},
  abstract  = {Die vorliegende Erfindung betrifft ein energieeffizientes, umweltfreundliches und kosteng{\"u}nstiges, vorzugsweise kontinuierliches Verfahren zur Herstellung von Biomethan aus kohlenstoffhaltigen Einsatzstoffen durch die Kombination der thermischen Vergasung mit mikrobiologischer Methan-Erzeugung.},
  language  = {de}
}
@phdthesis{Pettrak2010,
  author    = {Pettrak, J{\"u}rgen},
  title     = {Nutzung nachwachsender Rohstoffe bei der Herstellung thermoplastischer Elastomere aus Folgeprodukten der Olefinmetathese},
  publisher = {Technische Universit{\"a}t M{\"u}nchen},
  address   = {M{\"u}nchen},
  pages     = {137 Seiten},
  year      = {2010},
  abstract  = {Metathese von {\"O}ls{\"a}ure und Derivaten ist ein interessanter Weg f{\"u}r die Synthese bifunktioneller Verbindungen aus nachwachsenden Rohstoffen. Verwendet wurden Ru-Katalysatoren der zweiten Generation, welche eine hohe Toleranz gegen{\"u}ber funktionellen Gruppen und Verunreinigungen aufweisen. Trotz des Einsatzes technischer Edukte waren Umsetzungen mit niedrigen Katalysatormengen (0.001 - 0.01 mol-\%) m{\"o}glich, mit Ausbeuten entsprechend der Literatur. Kreuzmetathesen erm{\"o}glichten variable Kettenl{\"a}ngen und Funktionalit{\"a}ten der Monomere, die Produktgewinnung ist jedoch aufw{\"a}ndig. Selbstmetathese lieferte C18-bifunktionelle Verbindungen, welche einfach durch Destillation oder Kristallisation isoliert werden k{\"o}nnen. Neben der katalystischen Umsetzung wurde auch die Produktgewinnung untersucht und f{\"u}r ausgew{\"a}hlte Produkte auch im gr{\"o}ßeren Maßstab durchgef{\"u}hrt.},
  language  = {de}
}
@article{RieplPettrakFaulstichetal.2010,
  author    = {Riepl, Herbert Matthias and Pettrak, J{\"u}rgen and Faulstich, Martin and Herrmann, Wolfgang Anton},
  title     = {Self metathesis of fatty alcohols and amines to provide monomers for polyester and polyamide products},
  series = {Macromolecular Symposia},
  volume    = {293},
  journal   = {Macromolecular Symposia},
  number    = {1},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1521-3900 (eISSN)},
  doi       = {10.1002/masy.200900041},
  pages     = {39 -- 42},
  year      = {2010},
  abstract  = {Self metathesis of oleochemicals offers a variety of bifunctional compounds, that can be used as monomer for polymer production. Many precursors are in huge scales available, like oleic acid ester (biodiesel), oleyl alcohol (tensides), oleyl amines (tensides, lubricants). We show several ways to produce and separate and purify C18-α,ω-bifunctional compounds, using Grubbs 2nd Generation catalysts, starting from technical grade educts.},
  language  = {en}
}
@book{Pettrak2014,
  author    = {Pettrak, J{\"u}rgen},
  title     = {Nutzung nachwachsender Rohstoffe bei der Herstellung thermoplastischer Elastomere aus Folgeprodukten der Olefinmetathese},
  publisher = {Attenkofer},
  address   = {Straubing},
  isbn      = {978-3-942742-35-1},
  pages     = {147 Seiten},
  year      = {2014},
  language  = {de}
}
@article{GrosshauserPettrak2023,
  author    = {Großhauser, Christian and Pettrak, J{\"u}rgen},
  title     = {Die Rolle des Wasserstoffs in der Abwasserbehandlung},
  series = {Wasser und Abfall},
  journal   = {Wasser und Abfall},
  number    = {7/8},
  publisher = {Springer Fachmedien},
  address   = {Wiesbaden},
  issn      = {1436-9095},
  doi       = {10.1007/s35152-023-1444-4},
  year      = {2023},
  abstract  = {Die Bereitstellung von nachhaltig erzeugtem Wasserstoff als Energietr{\"a}ger und Rohstoff ist eine wichtige Schl{\"u}sseltechnologie sowohl als Ersatz f{\"u}r fossile Energietr{\"a}ger, aber auch als Produkt im Zusammenhang mit Kreislaufprozessen. In der Abwasserbehandlung bestehen verschiedene M{\"o}glichkeiten Wasserstoff herzustellen. Mehrere Wege, m{\"o}gliche Synergien, aber auch deren Nachteile werden vorgestellt.},
  language  = {de}
}