The new COST-G deterministic signal model

The precise orbit determination (POD) of Low Earth Orbiters (LEO), e.g. the Copernicus Sentinel Earth observation satellites, relies on the precise knowledge of the Earth gravity field and its variations with time. The most precise observation of time-variable gravity on a global scale is currently provided by the GRACE-FO satellites. But the monthly gravity field solutions are released with a latency of approx. 2 months, therefore they cannot be used for operational POD. We present a deterministic signal model (DSM) that is fitted to the time-series of COST-G combined monthly gravity fields and describe the differences with respect to the available long-term gravity models including seasonal and secular time-variations. To validate the DSM, dynamic POD of the Sentinel-2B, -3B and -6A satellites is performed based on long-term or monthly gravity field models, and on the COST-G DSM. We evaluate the model quality on the basis of carrier phase residuals, orbit overlap analysis and independent satellite laser ranging observations, and study the limitation on orbit altitude posed by the reduced spherical harmonic resolution of the monthly models and the DSM. The COST-G DSM is updated quarterly with the most recent GRACE-FO combined monthly gravity fields. It is foreseen to apply a sliding window approach with flexible window length to allow for an optimal adjustment in case of singular events like major earthquakes

Precise orbit determination based on COST-G time-variable gravity fields

The Combination Service for Time-variable Gravity fields (COST-G) provides monthly gravity fields, combined from the individual solutions of the COST-G analysis centers and additional partner analysis centers derived from GRACE/GRACE-FO inter-satellite GPS and K-band ranging data. The Precise Orbit Determination (POD) of Earth observation satellites in Low Earth Orbits (LEO) relies on accurate and up-to-date information on the Earthâ?Ts gravity field and its time-variations. We study POD results of the Sentinel-2B, -3B and -6A satellites based either on the monthly COST-G combinations, available with a latency of 2-3 months, or on Fitted Signal Models (FSM) derived on the basis of the COST-G time-series of monthly gravity fields, which allow for the prediction of secular and seasonal gravity variations over several months and therefore may be used in operational LEO POD. Special focus is put on the fit interval of the FSM and the impact of episodic events, e.g. the massive ice melt in Greenland in the summer of 2019, on the performance of the gravity-predictions for POD

Characterisation of the autoinmune antibody repertoire of Parkinson's disease patients by systematic screening of protein arrays

Comunicaciones a congreso

A Case for a New IT Ecosystem: On-The-Fly Computing

The complexity of development and deployment in today’s IT world is enormous. Despite the existence of so many pre-fabricated components, frameworks, cloud providers, etc., building IT systems still remains a major challenge and most likely overtaxes even a single ambi- tious developer. This results in spreading such develop- ment and deployment tasks over different team members with their own specialization. Nevertheless, not even highly competent IT personnel can easily succeed in developing and deploying a nontrivial application that comprises a multitude of different components running on different platforms (from frontend to backend). Current industry trends such as DevOps strive to keep development and deployment tasks tightly integrated. This, however, only partially addresses the underlying complexity of either of these two tasks. But would it not be desirable to simplify these tasks in the first place, enabling one person – maybe even a non-expert – to deal with all of them? Today’s approaches to the development and deployment of complex IT applications are not up to this challenge. ‘‘On-The-Fly Computing’’ offers an approach to tackle this challenge by providing complex IT services through largely automated configuration and execution. The configuration of such services is based on simple, flexibly combinable services that are provided by different software providers and traded in a market. This constitutes a highly relevant challenge for research in many branches of computer science, informa- tion systems, business administration, and economics. In this research note, it is analyzed which pieces of this new ‘‘On-The-Fly Computing’’ ecosystem already exist and where additional, often significant research efforts are necessary

An endoplasmic reticulum (ER)-directed fusion protein comprising a bacterial subtilisin domain and the human cytokine interleukin 6 is efficiently cleaved in planta

A major limitation of plant bioreactors is the lack of suitable and cost-effective purification methods for the extraction of pharmaceutical-grade proteins. In contrast to that, there are numerous established purification systems for heterologous proteins, expressed in Escherichia coli, which are used for the commercial production of therapeutic proteins. Therefore, we wanted to adapt the BioRad Profinity eXact<sup>TM</sup> one-step protein purification system (originally designed for microbial expression platforms) to purify recombinant proteins in crude plant extracts. This system based on the prodomain of microbial subtilase as fusion partner and a column-bound subtilisin protease. The engineered protease captures and cleaves the fusion protein, retaining the tag and releasing the native protein into the eluate. The subtilase tag was fused to human interleukin 6 (IL6) and transiently expressed in Nicotiana benthamiana leaves using the MagnICON system. The fusion protein was expressed at lower levels than native IL6, suggesting it is expressed less efficiently and/or has a lower stability. However, free IL6 was also detected in the extract and was unaffected by the addition of protease inhibitors during extraction, suggesting that the fusion protein is cleaved in planta by endogenous proteases. Purification of the recombinant protein using the Profinity eXact<sup>TM</sup> system reduced the yield still further. The inefficient production of tagged IL6, coupled with the extensive losses during purification, indicate that the Profinity eXact<sup>TM</sup> system is not suitable for the extraction of IL6 from crude plant extracts.Keywords: Tobacco, transient expression, endoplasmic reticulum, Profinity protein purification, partial cleavageAfrican Journal of Biotechnology Vol. 12(3), pp. 311-31

Recombinant production of the human complement factor 5a in Escherichia coli

Up to now, the human complement factor 5a (C5a) has only been produced in small quantities in Escherichia coli in a soluble, bioactive conformation, which is not suitable for commercial production systems. This stems from the extremely high instability of C5a, as well as its aggregation-prone nature. Therefore, we analyzed several different methods for optimizing the solubility and biological activity of C5a produced by E. coli. The solubility of C5a was efficiently improved by expressing it as a glutathione-S-transferase (GST) fusion protein and, to a lesser extent, by lowering the cultivation temperature. Neither reducing the inductor concentration (isopropylthio-β-galactoside, IPTG) of the T7lac promotor nor the concomitant overexpression of endogenous chaperones was effective. However, the biological activity of the protein was improved by the overexpression of chaperones together with cultivation at 22°C, while fusion to GST slightly reduced its activity. Consequently, low cultivation temperature and the overexpression of chaperones seem to be the optimal strategy for expression of appropriate amounts of soluble and functional C5a. These findings should be the basis for the transfer to large-scale fermentation. Using C5a as an example, we showed that strain engineering in combination with specific cultivation conditions improve the production of difficult-to-express proteins in appropriate amounts and in a functional conformation facilitating the commercial manufacturing under good manufacturing practices (GMP) conditions.Keywords: Complement factor 5a (C5a), Origami 2, BL21, periplasm, cytoplasm, chaperones, Glutathione-S-Transferase (GST), temperatur

COST-G gravity field models: application in SLR orbit determination

The Combination Service for Time-varible Gravity fields (COST-G), as a product center of the International Gravity Field Service (IGFS) of the International Association of Geodesy (IAG), provides monthly GRACE, GRACE-FO and Swarm gravity fields that are combined from the contributions of the associated analysis centers and partner analysis centers worldwide. To support operational Precise Orbit Determination (POD) of Low Earth Orbiters (LEO), where the GRACE-FO monthly gravity fields cannot meet the latency requirenments, COST-G is providing a Fitted Signal Model (FSM) that allows for the prediction of temporal gravity field variations. The COST-G FSM is updated quarterly with the latest GRACE-FO data and therefore is always based on the most recent gravity fields available. We will present the COST-G FSM and its application for the daily SLR routine processing of LAGEOS/ETALON, as well as LARES orbit determination