| 44631. |
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| 44632. |
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| 44633. |
- Kuhn, A., et al.
(author)
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D-2-hydroxyglutarate metabolism is linked to photorespiration in the shm1-1 mutant
- 2013
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In: Plant Biology. - : Wiley. - 1435-8603. ; 15:4, s. 776-784
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Journal article (peer-reviewed)abstract
- The Arabidopsis mutant shm1-1 is defective in mitochondrial serine hydroxymethyltransferase 1 activity and displays a lethal photorespiratory phenotype at ambient CO2 concentration but grows normally at high CO2. After transferring high CO2-grown shm1-1 plants to ambient CO2, the younger leaves remain photosynthetically active while developed leaves display increased yellowing and decreased FV/FM values. Metabolite analysis of plants transferred from high CO2 to ambient air indicates a massive light-dependent (photorespiratory) accumulation of glycine, 2-oxoglutarate (2OG) and D-2-hydroxyglutarate (D-2HG). Amino acid markers of senescence accumulated in ambient air in wild-type and shm1-1 plants maintained in darkness and also build up in shm1-1 in the light. This, together with an enhanced transcription of the senescence marker SAG12 in shm1-1, suggests the initiation of senescence in shm1-1 under photorespiratory conditions. Mitochondrial D-2HG dehydrogenase (D-2HGDH) converts D-2HG into 2OG. In vitro studies indicate that 2OG exerts competitive inhibition on D-2HGDH with a Ki of 1.96 mm. 2OG is therefore a suitable candidate as inhibitor of the in vivo D-2HGDH activity, as 2OG is produced and accumulates in mitochondria. Inhibition of the D-2HGDH by 2OG is likely a mechanism by which D-2HG accumulates in shm1-1, however it cannot be ruled out that D-2HG may also accumulate due to an active senescence programme that is initiated in these plants after transfer to photorespiratory conditions. Thus, a novel interaction of the photorespiratory pathway with cellular processes involving D-2HG has been identified.
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| 44634. |
- Kühn, Clemens, 1981, et al.
(author)
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Formal Representation of the High Osmolarity Glycerol Pathway in Yeast
- 2009
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In: Genome informatics. International Conference on Genome Informatics. - 0919-9454. ; 22, s. 69-83
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Journal article (peer-reviewed)abstract
- The high osmolarity glycerol (HOG) signalling system in yeast belongs to the class of Mitogen Activated Protein Kinase (MAPK) pathways that are found in all eukaryotic organisms. It includes at least three scaffold proteins that form complexes, and involves reactions that are strictly dependent on the set of species bound to a certain complex. The scaffold proteins lead to a combinatorial increase in the number of possible states. To date, representations of the HOG pathway have used simplifying assumptions to avoid this combinatorial problem. Such assumptions are hard to make and may obscure or remove essential properties of the system.This paper presents a detailed generic formal representation of the HOG system without such assumptions, showing the molecular interactions known from the literature. The model takes complexes into account, and summarises existing knowledge in an unambiguous and detailed representation. It can thus be used to anchor discussions about the HOG system. In the commonly used Systems Biology Markup Language (SBML), such a model would need to explicitly enumerate all state variables. The \emph{Kappa} modelling language which we use supports representation of complexes without such enumeration.To conclude, we compare \emph{Kappa} with a few other modelling languages and software tools that could also be used to represent and model the HOG system.
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| 44635. |
- Kuhn, C., et al.
(author)
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Modeling yeast osmoadaptation at different levels of resolution
- 2013
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In: Journal of Bioinformatics and Computational Biology. - : World Scientific Pub Co Pte Ltd. - 0219-7200 .- 1757-6334. ; 11:2
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Journal article (peer-reviewed)abstract
- We review the proposed mathematical models of the response to osmotic stress in yeast. These models mainly differ in the choice of mathematical representation (e. g. Bayesian networks, ordinary differential equations, or rule-based models), the extent to which the modeling is data-driven, and predictability. The overview exemplifies how one biological system can be modeled with various modeling techniques and at different levels of resolution, and how the choice typically is based on the amount and quality of available data, prior information of the system, and the research question in focus. As a natural part of the overview, we discuss requirements, advantages, and limitations of the different modeling approaches.
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| 44636. |
- Kühne, Thomas, et al.
(author)
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Performance simulation of a 5G hybrid beamforming millimeter-wave system
- 2020
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In: WSA 2020 - 24th International ITG Workshop on Smart Antennas.
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Conference paper (peer-reviewed)abstract
- Millimeter-wave systems are the next step to increase the data rate of 5G mobile communication networks. Hybrid analog-digital beamforming is one of the core technologies to enable millimeter-wave communication. Both the theoretical basics and the hardware design have been investigated in recent years. Current research projects like the European SERENA project strive to develop platforms to demonstrate the performance gain of complete systems. We present a simulation based analysis of a planned proof-of-concept system to evaluate the influence of design decisions and hardware impairments. We use a geometry-based stochastic channel simulator and simulate both certain hardware aspects and signal processing parts. We focus on the signal processing parts directly related to the hybrid architecture used for multi user MIMO precoding like the initial link acquisition and the data precoding. We use our own state-of-the-art algorithms for these parts.
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| 44637. |
- Kuhrmann, Marco, et al.
(author)
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Preface
- 2018
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In: Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics). - 1611-3349 .- 0302-9743. ; 11271 LNCS, s. V-VI
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Conference paper (other academic/artistic)
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| 44638. |
- Kuhrmann, Marco, et al.
(author)
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Walking through the method zoo: Does higher education really meet software industry demands?
- 2019
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In: Proceedings - 2019 IEEE/ACM 41st International Conference on Software Engineering: Software Engineering Education and Training, ICSE-SEET 2019. - : IEEE. ; , s. 1-11
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Conference paper (peer-reviewed)abstract
- Software engineering educators are continually challenged by rapidly evolving concepts, technologies, and industry demands. Due to the omnipresence of software in a digitalized society, higher education institutions (HEIs) have to educate the students such that they learn how to learn, and that they are equipped with a profound basic knowledge and with latest knowledge about modern software and system development. Since industry demands change constantly, HEIs are challenged in meeting such current and future demands in a timely manner. This paper analyzes the current state of practice in software engineering education. Specifically, we want to compare contemporary education with industrial practice to understand if frameworks, methods and practices for software and system development taught at HEIs reflect industrial practice. For this, we conducted an online survey and collected information about 67 software engineering courses. Our findings show that development approaches taught at HEIs quite closely reflect industrial practice. We also found that the choice of what process to teach is sometimes driven by the wish to make a course successful. Especially when this happens for project courses, it could be beneficial to put more emphasis on building learning sequences with other courses.
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| 44639. |
- Kuhrmann, Marco, et al.
(author)
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What Makes Agile Software Development Agile
- 2022
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In: IEEE Transactions on Software Engineering. - 0098-5589 .- 1939-3520. ; 48:9, s. 3523-3539
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Journal article (peer-reviewed)abstract
- Together with many success stories, promises such as the increase in production speed and the improvement in stakeholders' collaboration have contributed to making agile a transformation in the software industry in which many companies want to take part. However, driven either by a natural and expected evolution or by contextual factors that challenge the adoption of agile methods as prescribed by their creator(s), software processes in practice mutate into hybrids over time. Are these still agile In this article, we investigate the question: what makes a software development method agile We present an empirical study grounded in a large-scale international survey that aims to identify software development methods and practices that improve or tame agility. Based on 556 data points, we analyze the perceived degree of agility in the implementation of standard project disciplines and its relation to used development methods and practices. Our findings suggest that only a small number of participants operate their projects in a purely traditional or agile manner (under 15%). That said, most project disciplines and most practices show a clear trend towards increasing degrees of agility. Compared to the methods used to develop software, the selection of practices has a stronger effect on the degree of agility of a given discipline. Finally, there are no methods or practices that explicitly guarantee or prevent agility. We conclude that agility cannot be defined solely at the process level. Additional factors need to be taken into account when trying to implement or improve agility in a software company. Finally, we discuss the field of software process-related research in the light of our findings and present a roadmap for future research.
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| 44640. |
- Kuimova, M. K., et al.
(author)
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Determination of the triplet state energies of a series of conjugated porphyrin oligomers
- 2007
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In: Photochemical and Photobiological Sciences. - : Springer Science and Business Media LLC. - 1474-9092 .- 1474-905X. ; 6:6, s. 675-682
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Journal article (peer-reviewed)abstract
- We report a systematic study of the photophysical parameters relevant to photodynamic therapy (PDT) by a new type of sensitizers, conjugated porphyrin oligomers. Due to the strong nonlinear properties of oligomers containing 2, 4 and 8 porphyrin units, these molecules are attractive candidates for PDT via multiphoton excitation. The triplet state energy levels for all molecules have been determined by the triplet quenching method, phosphorescence measurements and DFT calculations. We find that the triplet energies of all the oligomers are sufficient to generate singlet oxygen, > 94 kJ mol(-1). However, low singlet oxygen quantum yields are observed for the tetramer and the octamer, as compared to the conjugated dimer and monomeric porphyrin, reflecting the decrease in triplet yield. Thus the conjugated porphyrin dimer is the most promising core structure for PDT applications via multiphoton excitation.
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