The mammalian gene function resource: the International Knockout Mouse Consortium.

In 2007, the International Knockout Mouse Consortium (IKMC) made the ambitious promise to generate mutations in virtually every protein-coding gene of the mouse genome in a concerted worldwide action. Now, 5 years later, the IKMC members have developed high-throughput gene trapping and, in particular, gene-targeting pipelines and generated more than 17,400 mutant murine embryonic stem (ES) cell clones and more than 1,700 mutant mouse strains, most of them conditional. A common IKMC web portal (www.knockoutmouse.org) has been established, allowing easy access to this unparalleled biological resource. The IKMC materials considerably enhance functional gene annotation of the mammalian genome and will have a major impact on future biomedical research

Framework and baseline examination of the German National Cohort (NAKO)

The German National Cohort (NAKO) is a multidisciplinary, population-based prospective cohort study that aims to investigate the causes of widespread diseases, identify risk factors and improve early detection and prevention of disease. Specifically, NAKO is designed to identify novel and better characterize established risk and protection factors for the development of cardiovascular diseases, cancer, diabetes, neurodegenerative and psychiatric diseases, musculoskeletal diseases, respiratory and infectious diseases in a random sample of the general population. Between 2014 and 2019, a total of 205,415 men and women aged 19–74 years were recruited and examined in 18 study centres in Germany. The baseline assessment included a face-to-face interview, self-administered questionnaires and a wide range of biomedical examinations. Biomaterials were collected from all participants including serum, EDTA plasma, buffy coats, RNA and erythrocytes, urine, saliva, nasal swabs and stool. In 56,971 participants, an intensified examination programme was implemented. Whole-body 3T magnetic resonance imaging was performed in 30,861 participants on dedicated scanners. NAKO collects follow-up information on incident diseases through a combination of active follow-up using self-report via written questionnaires at 2–3 year intervals and passive follow-up via record linkages. All study participants are invited for re-examinations at the study centres in 4–5 year intervals. Thereby, longitudinal information on changes in risk factor profiles and in vascular, cardiac, metabolic, neurocognitive, pulmonary and sensory function is collected. NAKO is a major resource for population-based epidemiology to identify new and tailored strategies for early detection, prediction, prevention and treatment of major diseases for the next 30 years. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10654-022-00890-5

The mammalian gene function resource: The International Knockout Mouse Consortium

In 2007, the International Knockout Mouse Consortium (IKMC) made the ambitious promise to generate mutations in virtually every protein-coding gene of the mouse genome in a concerted worldwide action. Now, 5 years later, the IKMC members have developed highthroughput gene trapping and, in particular, gene-targeting pipelines and generated more than 17,400 mutant murine embryonic stem (ES) cell clones and more than 1,700 mutant mouse strains, most of them conditional. A common IKMC web portal (www.knockoutmouse.org) has been established, allowing easy access to this unparalleled biological resource. The IKMC materials considerably enhance functional gene annotation of the mammalian genome and will have a major impact on future biomedical research

Characterization and Long-Term Testing of Solid Oxide Electrolyzer Cells

A reliable energy supply which is based on increasing shares of sustainable and renewable energy sources, such as wind power and solar energy, requires appropriate storage technologies. Hydrogen as energy carrier, produced by water electrolysis using electric current from regenerative energy sources, offers a high potential in this respect. A very efficient option to produce hydrogen in this way is high-temperature steam electrolysis based on solid oxide electrolyzer cells (SOEC). This technology requires operating temperatures in the range of 700-1000 °C and offers some additional advantages compared to low temperature electrolysis techniques. The higher operating temperature results in faster reaction kinetics thus enabling potentially high energy efficiency. From a thermodynamic point of view, part of the energy demand for the endothermic water splitting reaction can be obtained from heat produced within the cell. The electric energy demand can be further significantly reduced if high temperature heat from renewable energy sources such as geothermal or solar thermal power or waste heat from industrial processes is available. Furthermore, it is possible with high temperature electrolysis to not only split water but also carbon dioxide or a mixture of both to produce synthesis gas (syngas) or other energy carriers such as methane or methanol by subsequent catalytic conversion. For a further development of this promising technology, development work on materials and cells as well as extensive operational experience is still needed. A main objective is to develop highly efficient and long-term stable cells and stacks using novel electrode materials and to improve the degradation behavior by elucidating the relevant degradation mechanisms. To this aim, German Aerospace Center (DLR) and Forschungszentrum Jülich (JÜLICH) who have both long experience in the development of SOFC/SOEC technology started a joint project in the frame of the “Helmholtz Energy Alliance” on electrochemical energy storage and conversion. Cathode-supported cells containing novel perovskite-type air electrodes were fabricated by ceramic processing and sintering for electrochemical characterization in electrolysis operating mode. The selection and preparation of electrode materials and the process of cell manufacturing is described. A new test bench has been installed which allows measuring polarization curves of 4 cells simultaneously under relevant SOFC and SOEC conditions as well as performing long-term durability measurements. Results of electrochemical measurements performed at different operational conditions, such as different steam content and operating temperature, are presented. After operation the cells were investigated by post-test analytical methods; hereby special emphasis is put on the detailed investigation of degradation phenomena and mechanisms by applying numerous characterization techniques

Study of Detailed Degradation Behavior of Solid Oxide Electrolyzer Cells (SOEC)

High temperature electrolysis has a high potential for the efficient production of hydrogen or syngas. For a further development of this promising technology, development work on materials and cells as well as extensive operational experience is still needed. A main objective is to develop highly efficient and long-term stable cells and stacks using novel electrode materials and to improve the degradation behaviour by elucidating the relevant degradation mechanisms. Within a joint project in the frame of the “Helmholtz Energy Alliance” German Aerospace Center (DLR) and Forschungszentrum Jülich (JÜLICH) started a detailed study on the performance and degradation behaviour of planar SOE cells. Cathode-supported cells containing novel perovskite-type air electrodes were fabricated by ceramic processing and sintering for electrochemical characterization in electrolysis operating mode. A special test bench has been installed which allows measuring polarization curves of 4 cells simultaneously under relevant SOEC conditions. For a systematic investigation of the influence of the operating parameters temperature, fuel gas humidification and current density on SOEC long-term degradation a series of measurements over 1000 hours in the temperature range 750-850 °C with different fuel gas humidity (40-80 mol%) and different current densities between 0 and 1.5 A/cm2 has been performed. The progress of degradation was monitored in-operando approximately every 150 h by impedance spectroscopy. It was possible to differentiate different electrode processes, a mass transport limitation on the fuel electrode and the electrolyte resistance. Post-mortem investigations have been conducted to localize and identify the rate limiting processes and to clarify the correlation between degradation processes and operational parameters. In this paper the selection and preparation of electrode materials and the process of cell manufacturing as well as the experimental setup for cell characterization and long-term measurements are described. Results of electrochemical cell characterization performed at different operational conditions are shown and observed degradation phenomena and their underlying mechanisms based on different electrochemical processes are explained

Understanding SOEC Degradation Processes by means of a Systematic Parameter Study

Solid Oxide Electrolysis Cell (SOEC) technology is a promising approach for storing large quantities of electrical energy. One major obstacle for wide spread implementation is the cell’s limited durability due to a number of degradation phenomena. Therefore, understanding the origin and evolution of degradation processes is essential for developing long-term operating SOEC technology. The present study aims at identifying and characterizing the predominant degradation phenomena of planar Ni/YSZ|YSZ|CGO|LSCF anode supported cells from CeramTec, Germany, operating on H2/H2O mixtures, by investigating the influence of operating parameters on cell deterioration. In order to systematically study the influence of temperature in a range between 750°C and 850°C and fuel gas humidity in a range between 40 mol.-% and 80 mol.-% on SOEC degradation, a matrix of experiments over 1000 hours each was devised. Furthermore, the influence of the current density was determined in a range between OCV and 1.5 A·cm‒2 for each investigated combination of temperature and humidity, thereby gaining insight into coupled correlations between operating parameters and SOEC degradation. In order to shed light on underlying physico-chemical processes and performance limiting factors a detailed physico-chemical modeling approach was employed. A more detailed description of the model and the results are given in a second contribution to this conference. Periodic in-situ impedance measurements were used to track the development of each individual process over the duration of the experiment. The observed degradation characteristics of each process vary greatly including constant degradation, decreasing degradation and stable behavior, depending on the nature of the processes as well as the operating parameters applied. Finally the in-situ degradation observations were substantiated by post mortem analyses. In order to identify microstructural changes especially those appeared in electrolyte and fuel electrode, SEM measurements were conducted while EDX measurements were used to monitor elemental enrichment or depletion as well as impurity deposition. Furthermore, changes in surface and bulk crystallography were investigated by XPS and XRD measurements. Hence, this systematic experimental study on SOEC degradation coupled with the physico-chemical understanding from the modeling approach allows not only the development of strategies for increasing cell’s lifetime but could also be used to determine experimental protocols for accelerated degradation

A parameter study of solid oxide electrolysis cell degradation: Microstructural changes of the fuel electrode

A parameter study of 20 solid oxide electrolysis cells was carried out to systematically investigate long-term degradation each over 1,000 h under variation of temperature, humidity and current density. The influence of operating temperature was investigated between 750 and 850 °C, the humidity ranged from 40 % to 80 % H2O, and the current density varied between open circuit voltage (OCV) and 1.5 A·cm–2. The progress of degradation was monitored in-situ by electrochemical impedance spectroscopy. Five different contributions to the spectra were identified by calculating the distribution of relaxation times and separated via a complex non-linear square fitting routine. The present work focuses on the degradation of the fuel electrode. From SEM analysis, Ni depletion and an increased pore fraction close to the electrode/electrolyte interface was derived, which is correlated with an increased ohmic resistance of the cells. This unidirectional transport of Ni away from the fuel electrode/electrolyte interface leads to an effective electrolyte extension and is the main source of degradation. Ni depletion is shown to be driven by current density and its extent is shown to be dependent on the complex interplay between the operating parameters current density, anode overpotential, humidity and temperature. It is particularly pronounced for pH2O larger than 0.8 atm and temperatures above 800 °C. Furthermore, the fuel electrode electrochemistry also exhibits degradation in the high-frequency region around 10 exp4 Hz