RosettaBackrub--a web server for flexible backbone protein structure modeling and design.

The RosettaBackrub server (http://kortemmelab.ucsf.edu/backrub) implements the Backrub method, derived from observations of alternative conformations in high-resolution protein crystal structures, for flexible backbone protein modeling. Backrub modeling is applied to three related applications using the Rosetta program for structure prediction and design: (I) modeling of structures of point mutations, (II) generating protein conformational ensembles and designing sequences consistent with these conformations and (III) predicting tolerated sequences at protein-protein interfaces. The three protocols have been validated on experimental data. Starting from a user-provided single input protein structure in PDB format, the server generates near-native conformational ensembles. The predicted conformations and sequences can be used for different applications, such as to guide mutagenesis experiments, for ensemble-docking approaches or to generate sequence libraries for protein design

From Lampoldshausen to Orbit: DLR Spin-off GreenDelta and the Development Status of Green Propellant Thrusters Based on H\u3csub\u3e2\u3c/sub\u3eO\u3csub\u3e2\u3c/sub\u3e and N\u3csub\u3e2\u3c/sub\u3eO

The German Aerospace Center\u27s Institute of Space Propulsion in Lampoldshausen has more than a decade of experience in green propellant research and green propulsion hardware development. In the frame of internal research projects as well as ESA and third-party projects DLR employees gained a deep and extensive knowledge of propulsion hardware. Based on this knowledge, thrusters and propulsion hardware were developed in-house and the TRL was increased step by step. Currently, the two most promising technologies are: the HyNOx bipropellant technology, based on nitrous oxide and hydrocarbon fuels, as well as the hypergolic HIP_11 technology. The HyNOx bipropellant offers a high Isp, non-toxic components, self-pressurized propulsion systems, easy handling and very low cost. HIP_11 is a patented, hypergolic combination based on hydrogen peroxide and ionic liquid fuels, which offers a comparable Isp, significantly reduced costs, and easy to handle propellants. To commercialize the two propulsion technologies, a DLR spin-off called GreenDelta will be founded in summer 2023. The preparation of the spin-off is currently funded by the Helmholtz Association and DLR. This paper gives an overview on the development of the two technologies and their development status. First thrusters from GreenDelta will be commercially available at Q4 2023

From Lampoldshausen to Orbit: DLR Spin-off GreenDelta and the Development Status of Green Propellant Thrusters Based on H2O2 and N2O

The German Aerospace Center's Institute of Space Propulsion in Lampoldshausen has more than a decade of experience in green propellant research and green propulsion hardware development. In the frame of internal research projects as well as ESA and third-party projects DLR employees gained a deep and extensive knowledge of propulsion hardware. Based on this knowledge, thrusters and propulsion hardware were developed in-house and the TRL was increased step by step. Currently, the two most promising technologies are: the HyNOx bipropellant technology, based on nitrous oxide and hydrocarbon fuels, as well as the hypergolic HIP_11 technology. The HyNOx bipropellant offers a high Isp, non-toxic components, self-pressurized propulsion systems, easy handling and very low cost. HIP_11 is a patented, hypergolic combination based on hydrogen peroxide and ionic liquid fuels, which offers a comparable Isp, significantly reduced costs, and easy to handle propellants. To commercialize the two propulsion technologies, a DLR spin-off called GreenDelta will be founded in summer 2023. The preparation of the spin-off is currently funded by the Helmholtz Association and DLR. This paper gives an overview on the development of the two technologies and their development status. First thrusters from GreenDelta will be commercially available at Q4 2023

From Lampoldshausen to Space: DLR Spin-off InSpacePropulsion Technologies and the Development Status of Green Propellant Thrusters Based on H2O2 and N2O

The German Aerospace Center’s Institute of Space Propulsion in Lampoldshausen has more than a decade of experience in green propellant research and green propulsion hardware development. Over time, thrusters and propulsion hardware were developed in-house and the TRL of the hardware was increased step by step. Currently, the two most promising technologies are: the HyNOx bipropellant technology, based on nitrous oxide and hydrocarbon fuels, as well as the hypergolic HIP_11 technology. To commercialize the two propulsion technologies, a DLR spin-off called InSpacePropulsion Technologies will be founded in summer 2023. The preparation of the spin-off is currently funded by the Helmholtz Association and DLR. This paper gives an overview on the development of the two technologies and their development status

The Structure-Function Linkage Database

The Structure–Function Linkage Database (SFLD, http://sfld.rbvi.ucsf.edu/) is a manually curated classification resource describing structure–function relationships for functionally diverse enzyme superfamilies. Members of such superfamilies are diverse in their overall reactions yet share a common ancestor and some conserved active site features associated with conserved functional attributes such as a partial reaction. Thus, despite their different functions, members of these superfamilies ‘look alike’, making them easy to misannotate. To address this complexity and enable rational transfer of functional features to unknowns only for those members for which we have sufficient functional information, we subdivide superfamily members into subgroups using sequence information, and lastly into families, sets of enzymes known to catalyze the same reaction using the same mechanistic strategy. Browsing and searching options in the SFLD provide access to all of these levels. The SFLD offers manually curated as well as automatically classified superfamily sets, both accompanied by search and download options for all hierarchical levels. Additional information includes multiple sequence alignments, tab-separated files of functional and other attributes, and sequence similarity networks. The latter provide a new and intuitively powerful way to visualize functional trends mapped to the context of sequence similarity

How Recent is a Web Document?

One of the most important aspects of a Web document is its up-to-dateness or recency. Up-todateness is particularly relevant to Web documents because they usually contain content origining from different sources and being refreshed at different dates. Whether a Web document is relevant for a reader depends on the history of its contents and so-called external factors, i.e., the up-todateness of semantically related documents. In this paper, we approach automatic management of up-to-dateness of Web documents that are managed by an XML-centric Web content management system. First, the freshness for a single document is computed, taking into account its change history. A document metric estimates the distance between different versions of a document. Second, up-to-dateness of a document is determined based on its own history and the historical evolutions of semantically related documents

FSees: Customized Enumeration of Chemical Subspaces with Limited Main Memory Consumption

In the search for new marketable drugs, new ideas are required constantly. Particularly with regard to challenging targets and previously patented chemical space, designing novel molecules is crucial. This demands efficient and innovative computational tools to generate libraries of promising molecules. Here we present an efficient method to generate such libraries by systematically enumerating all molecules in a specific chemical space. This space is defined by a fragment space and a set of user-defined physicochemical properties (e.g., molecular weight, tPSA, number of H-bond donors and acceptors, or predicted logP). In order to enumerate a very large number of molecules, our algorithm uses file-based data structures instead of memory-based ones, thus overcoming the limitations of computer main memory. The resulting chemical library can be used as a starting point for computational lead-finding technologies, like similarity searching, pharmacophore mapping, docking, or virtual screening. We applied the algorithm in different scenarios, thus creating numerous target-specific libraries. Furthermore, we generated a fragment space from all approved drugs in DrugBank and enumerated it with lead-like constraints, thus generating 0.5 billion molecules in the molecular weight range 250–350

Experimental Investigation of Combustion Performances of a Green Hypergolic Bipropellant based on Hydrogen Peroxide

The present study examines the advancement of a promising low-toxicity hypergolic propellant combination called HIP_11 for in-space applications, developed as alternative to common toxic propellants. The fuel is an Energetic Ionic Liquid, storable, stable and simple to handle at ambient conditions, developed at the Institute of Space Propulsion, German Aerospace Centre (DLR). The compound shows hypergolicity behaviour when in contact with Hydrogen Peroxide and is a promising substitution to typical propellants. The present work describes the advancements in the development of HIP_11 through a dedicated experimental campaign, consisted in more than 50 successful firings, analysing and investigating the performances. The experiments are based on a small modulable thruster that allowed to study the efficiency and stability of combustion of the propellant combination while varying various design parameters of the thruster. Specifically, the effects of different injector designs, as well as variations in combustion chamber shape, characteristic length, and operating pressure have been thoroughly examined and analysed