Feature- and Structure-Preserving Network Reduction for Large-Scale Transmission Grids

Many countries are currently challenged with the extensive integration of renewable energy sources, which necessitates vast capacity expansion measures. These measures in turn require comprehensive power flow studies, which are often computationally highly demanding. In this work a reduction strategy for large-scale grid models is introduced which not only reduces the model complexity but also preserves the structure and designated grid features. The objective is to ensure that areas crucial to the behavior and the relation of all elements to their physical counterparts remain unchanged. This is accomplished through a specifically designed reduction method for suitable areas identified through topological, electrical and market-based approaches for which we provide an open-source implementation. We show that the proposed strategy adapts to various models and accomplishes a strong reduction of buses and branches while retaining a low dispatch and branch flow deviation. Furthermore, the accuracy of the reduction generalizes well to other scenarios.Comment: 13th IEEE PowerTech Conference 201

The link between cultural due diligence and socio-cultural post-merger integration management as a critical success factor in M&As

With the unchanging high failure rate of M&As, recent research is putting an increasing emphasis on Cultural Due Diligence (CDD) and socio-cultural Post-Merger Integration (PMI) Management. Nevertheless, the state of the art on CDD is still rare, leading to the fact that its actual value for a successful PMI remains unclear. Addressing this gap is the basic objective of this paper. In more detail the paper tries to clarify whether CDD is a necessary prerequisite for a successful PMI. The paper finds that the CDD process creates considerable value for the subsequent PMI as it facilitates a fast and smooth cultural integration and as such accelerates the operative integration of M&As.Die andauernd hohe Misserfolgsrate bei M&A hat zu einer intensiven wissenschaftlichen Beschäftigung mit Cultural Due Diligence (CDD) und sozio-kulturellem Post-Merger Integrationsmanagement geführt. Unklar ist jedoch inwieweit CDD zu einer gelungenen Post-merger Integration beiträgt. Am Beispiel einer Fallstudie zeigt der hier vorliegende Aufsatz, dass CDD eine wichtig Voraussetzung für eine gelungene Post-merger Integration ist, da er eine schnelle und reibungsarme kulturelle Integration ermöglicht und damit auch die operative Integration beschleunigt

Proteomic Techniques in the Physiological Proteomics Core Facility

poster abstractA new software package, IdentiQuantXL, has been developed in the Physiological Proteomics Core Facility to provide large-scale protein identification and label-free quantification using either low or high resolution LC-MS/MS data. Though many software packages have been developed to perform label-free quantification of proteins in complex biological samples using peptide intensities generated by liquid chromatography - tandem mass spectrometry (LC-MS/MS), two important issues hinder the use of peptide intensity measurements: (i) It is difficult to accurately determine the retention time of each peptide peak, especially for low resolution data, and (ii) many peptides cannot be used for protein quantification. To address these two key issues, we have developed a new method to enable accurate peptide peak retention time determination and multiple filters to eliminate unqualified peptides for protein quantification. Repeatability and linearity have been tested using ion trap-derived low resolution data from six very different samples, i.e., standard peptides, kidney tissue lysates, HT29-MTX cell lysates, depleted human serum, human serum albumin-bound proteins, and standard proteins spiked in kidney tissue lysates. In all these unique experiments, at least 90.8% of proteins (up to 1,390) had CVs ≤ 3 0% across 10 technique replicates, and at least 92.1% of proteins (up to 2,013) had R2 ≥ 0.9500 across 7 concentrations. The performance of our strategy was verified using identical amounts of standard protein (lysozyme) spiked in complex biological samples (cell culture media containing secreted proteins) with a CV of 8.6% across eight injections. The excellent performance was further confirmed by comparing label-free mass spectrometry to Western blot detection of prolactin, which was decreased 17.1fold in dwarfed mice compared to wild-type using the label-free quantification strategy and very low or undetectable using Western blot. The results indicate that our new platform, named IdentiQuantXL, accurately quantifies thousands of peptides and proteins in complex samples. It has been applied in the aqueous humor proteome in patients with Fuchs endothelial corneal dystrophy. While many software packages focus only on high resolution data, our strategy is designed for both high and low resolution data. Consequently, it is very useful for data generated by low resolution mass spectrometers such as the LTQ, especially when the dynamic exclusion of ions in data acquisition is enabled to obtain more MS/MS fragments of low-abundance peptides to maximally identify proteins in a complex biological sample. Supported by NIEHS RC2ES018810 and NIGMS R01GM08521

Palate anatomy and morphofunctional aspects of interpterygoid vacuities in temnospondyl cranial evolution

Temnospondyls were the morphologically and taxonomically most diverse group of early tetrapods with a near-global distribution during the Palaeozoic and Mesozoic. Members of this group occupied a range of different habitats (aquatic, amphibious, terrestrial), reflected by large morphological disparity of the cranium throughout their evolutionary history. A diagnostic feature of temnospondyls is the presence of an open palate with large interpterygoid vacuities, in contrast to the closed palate of most other early tetrapods and their fish-like relatives. Although the function of the interpterygoid vacuities has been discussed in the past, no quantitative studies have been performed to assess their biomechanical significance. Here, we applied finite element analysis, to test the possibility that the interpterygoid vacuities served for stress distribution during contraction of the jaw closing musculature. Different original and theoretical skull models, in which the vacuities differed in size or were completely absent, were compared for their mechanical performance. Our results demonstrate that palatal morphology played a considerable role in cranial biomechanics of temnospondyls. The presence of large cranial vacuities were found to offer the dual benefit of providing additional muscle attachment areas and allowing for more effective force transmission and thus an increase in bite force without compromising cranial stability

Analyse von Spannungstrichtern in Folge von Kurzschlüssen im deutschen Übertragungsnetz

Die Energiewende in Deutschland hat eine grundlegende Veränderung in der Erzeugungsstruktur zur Folge. Konventionelle Kraftwerke werden zunehmend von erneuerbaren Energien, welche überwiegend mit Wechselrichter an das Netz angeschlossen sind, verdrängt. Dies zieht eine Änderung des Kurzschlussverhaltens im System nach sich, da Wechselrichter einen geringeren Kurzschlussstrom als Synchrongeneratoren bereitstellen können. Folglich werden sich in Zukunft die Auswirkungen von Spannungseinbrüchen aufgrund von Kurzschlüssen im Übertragungsnetz im Vergleich zu heute ändern. Um diese Auswirkungen analysieren und quantifizieren zu können, werden im Rahmen des Beitrages verschiedene Auswertungsmöglichkeiten vorgestellt. Sie beruhen auf den Ergebnissen von dynamischen Simulationen im Zeitbereich (RMS-Simulationen) mit einem PSSNETOMACModell des deutschen Übertragungsnetzes und sollen zur besseren Vergleichbarkeit der Auswirkungen von Kurzschlüssen im Übertragungsnetz beitragen

Bioinformatic Analysis of Proteomic Changes That Occur in an Airway Epithelial Cell Line in Response to Exposure to Physiologically Relevant Concentrations of Carbon Nanotubes

poster abstractCarbon nanomaterials are widely produced and used in industry, medicine and scientific research. To examine the impact of acute exposure to nanoparticles on human health, the human airway epithelial cell line, Calu-3, was used to evaluate potential alterations in cellular function of airway epithelia after 24 hours exposure to different concentrations of two common carbon nanoparticles, single- and multi-wall carbon nanotubes (SWCNT, MWCNT). After exposure to the nanoparticles, label-free quantitative mass spectrometry (LFQMS) was used to study the differential protein expression in Calu-3 cells. Ingenuity Pathway Analysis (IPA) was used to conduct a bioinformatic analysis of proteins identified in LFQMS. Changes in protein abundance generated in response to 100 ng/ml exposure of both MWCNT and SWCNT suggest that cell functions of cell death and survival, cell-to-cell signaling and interaction, cellular assembly and organization, cellular growth and proliferation, infectious disease, molecular transport and protein synthesis are predicted to be effected. The majority of the protein changes represent a decrease in amount suggesting a shut down of metabolism to protect cells. The STRING database was used to analyze the protein networks in different functions. Interestingly some proteins like cadherin 1 (CDH1), signal transducer and activator of transcription 1 (STAT1), junction plakoglobin (JUP), apoptosis-associated speck-like protein containing a CARD (PYCARD), appear in several functions and tend to be in the center of the networks, which suggest they may play important roles in the cell function and activity

Effects of Carbon Nanotubes in Barrier Epithelial Cells via Effects on Lipid Bilayers

poster abstractCarbon nanotubes (CNTs) are one of many nanoparticles (NP) which are being developed as part of the burgeoning nanotechnology. The tubes have similar physical properties to known toxic materials, such as asbestos; yet there is a lack of evidence showing that they may be hazardous to humans, specifically to our barrier epithelial cells. We measured the effects of CNTs on human airway epithelial cells (Calu-3 cell line) using electrophysiology. This is a technique which measures transepithelial electrical resistance (TEER), a measure of monolayer integrity; and short circuit current (SCC) a measure of net ion transport across the cell. Exposed cells showed significant decreases in TEER when incubated for 48 hours with physiologically relevant concentrations of 4μg/cm2 - 0.4ng/cm2 of multi-wall (MW) and 4μg/cm2 - 0.04ng/cm2 single-wall (SW) CNT. TEER is a measure of barrier function which is important in cells that maintain separate compartments in the body. The impaired barrier function, despite sustained cell viability, led us to investigate the mechanism by which the CNT were interacting with the cell when applied topically. Model lipid membranes connected to an ion channel amplifier, Planar Bilayer Workstation (BLM), were used. Membranes were formed using the neutral diphytanoylphosphatidylcholine (DPhPC) and negatively charged diphytanoyl phosphatidylserine (DPhPS) lipids. CNTs caused random, transient currents ranging from 0pA to 6479pA to traverse the membrane. In the presence of Gramicidin A, an ion channel reporter protein, the tubes induced increased gramicidin channel formation in the membrane to saturation level and then membrane lysis. This CNT- lipid interaction indicated that short MWCNTs permits unregulated ion movement across the lipid membrane. Disruption in the selective permeability of the plasmalemma may impact the tissue’s barrier function

Mathematical Nanotoxicoproteomics: Quantitative Characterization of Effects of Multi-walled Carbon Nanotubes (MWCNT) and TiO2 Nanobelts (TiO2-NB) on Protein Expression Patterns in Human Intestinal Cells

Background: Various applications of nanosubstances in industrial and consumer goods sectors are growing rapidly because of their useful chemical and physical properties. Objectives: Assessment of hazard posed by exposure to nanosubstances is essential for the protection of human and ecological health. Methods: We analyzed the proteomics patterns of Caco-2/HT29-MTX cells in co-culture exposed for three and twenty four hours to two kinds of nanoparticles: multi-walled carbon nanotubes (MWCNT) and TiO2 nanobelts (TiO2-NB). For each nanosubstance cells were exposed to two concentrations of the material before carrying out proteomics analyses: 10 μg and 100 μg. In each case over 3000 proteins were identified. A mathematically based similarity index, which measures the changes in abundances of cellular proteins that are highly affected by exposure to the nanosubstances, was used to characterize toxic effects of the nanomaterials. Results: We identified 8 and 25 proteins, which are most highly affected by MWCNT and TiO2-NB, respectively. These proteins may be responsible for specific response of cells to the nanoparticles. Further 14 reported proteins are affected by either of the two nanoparticles and they are probably related to nonspecific toxic response of the cells. Conclusion: The similarity methods proposed in this paper may be useful in the management and visualization of the large amount of data generated by proteomics technologies

Delineation of Molecular Pathways Involved in Cardiomyopathies Caused by Troponin T Mutations

Familial hypertrophic cardiomyopathy (FHC) is associated with mild to severe cardiac problems and is the leading cause of sudden death in young people and athletes. Although the genetic basis for FHC is well-established, the molecular mechanisms that ultimately lead to cardiac dysfunction are not well understood. To obtain important insights into the molecular mechanism(s) involved in FHC, hearts from two FHC troponin T models (Ile79Asn [I79N] and Arg278Cys [R278C]) were investigated using label-free proteomics and metabolomics. Mutations in troponin T are the third most common cause of FHC, and the I79N mutation is associated with a high risk of sudden cardiac death. Most FHC-causing mutations, including I79N, increase the Ca(2+) sensitivity of the myofilament; however, the R278C mutation does not alter Ca(2+) sensitivity and is associated with a better prognosis than most FHC mutations. Out of more than 1200 identified proteins, 53 and 76 proteins were differentially expressed in I79N and R278C hearts, respectively, when compared with wild-type hearts. Interestingly, more than 400 proteins were differentially expressed when the I79N and R278C hearts were directly compared. The three major pathways affected in I79N hearts relative to R278C and wild-type hearts were the ubiquitin-proteasome system, antioxidant systems, and energy production pathways. Further investigation of the proteasome system using Western blotting and activity assays showed that proteasome dysfunction occurs in I79N hearts. Metabolomic results corroborate the proteomic data and suggest the glycolytic, citric acid, and electron transport chain pathways are important pathways that are altered in I79N hearts relative to R278C or wild-type hearts. Our findings suggest that impaired energy production and protein degradation dysfunction are important mechanisms in FHCs associated with poor prognosis and that cardiac hypertrophy is not likely needed for a switch from fatty acid to glucose metabolism