Lyotrop flüssigkristalline Benzolhexamin-Derivate

Preliminary results of investigations on hexa-amides of benzenehexamine demonstrate that these disc-shaped compounds - as such already known since 1937 - exhibit very interesting lyotropic liquid crystalline properties in various lipophilic solvents. At lower concentrations (e.g. about 20 wt.%) a nematic phase with an extraordinary wide range of stability (at least 65 °C!) has been found, whereas at higher concentrations a second mesophase exists with hexagonal structure

Abschlussbericht

In einer Kooperation mit Partnern aus Israel, Spanien, Italien und Deutschland wurde in RESIDUE ein Substrat aus Abfallstoffen entwickelt, welches zur Bodenverbesserung in der Landwirtschaft in Gebieten mit Wassermangel verwendet werden kann. Neben einer Düngung bewirkt die Zusammensetzung des Substrats auch eine Verbesserung der Rückhaltefunktionen des Bodens und verringert die Aufnahme von organischen Schadstoffen, die in solchen Gebieten oft mit dem Beregnungswasser auf die Pflanzen appliziert werden. Aufgrund des Wassermangels erfolgt die Beregnung oft mit ungeklärten oder wenig geklärten Abwässern. Die Einführung von Triggerwerten zur Wasserqualität führt nicht zum Ziel, da die Landwirtschaft keine Wahl hat, auf anderes Wasser auszuweichen, sollten Grenzwerte überschritten sein. Daher war es das Ziel des Projekts, ein Substrat zu entwickeln, das die Bodenfunktionen – hier Rückhalt und Abbaukapazität – stärkt und damit zu einer verbesserten Produktqualität führen kann. Zentraler Punkt war dabei, dass die Rohstoffe Abfälle sind, die ohnehin nicht anders zu verwerten sind. Ein Nebenaspekt ist die Verbesserung der „Carbon Sequestration“ in Böden durch die Verwendung von Biokohle für das Substrat. Das Fraunhofer IME hatte in dem Vorhaben die Rolle der Koordination. Zudem wurden Gewächhausexperimente mit 14C-radioaktiv markierten Referenzsubstanzen durchgeführt, um die Pflanzenaufnahme der Substanzen in eine ausgewählte Kulturpflanze (Lucerne) abhängig vom aufgebrachten Substrat zu untersuchen. Als Substrat wurde Klärschlamm vom Israelischen Partner zu Biokohle verarbeitet und diese Biokohle einem Klärschlammkompost während der Kompostierung zugegeben. Die Biokohle zeigte dabei einen Einfluss auf den Rotteprozess, der mit technischen Maßnahmen reduziert werden konnte. Das Rotteprodukt dagegen wurde als Verbesserung gegenüber einer Rotte ohne Biokohle beschrieben. Als Referenzsubstanzen wurden Carbamazepin und Lamotrigin auf der Grundlage einer Auswertung der vorhandenen Literatur ausgewählt. Beide wurden als 14C-Testsubstanzen für das Projekt eingesetzt. Der Spanische Partner CSIC untersuchte die Bioverfügbarkeit der Referenzsubstanzen in Gegenwart des entwickelten Substrats. Die Arbeiten des CSIC wurden zusammen mit dem IME in einem wissenschaftlichen Journal als open access Manuskript veröffentlicht: https://doi.org/10.1016/j.scitotenv.2023.168460 In Gewächhausversuchen mit Boden aus Israel und Substraten mit verschiedenen Anteilen Biokohle wurde die Aufnahme der Referenzsubstanzen, die mit dem Beregnungswasser eingetragen wurden, in Pflanzen untersucht. Es konnte ein deutlicher Effekt der Biokohle auf die Pflanzenaufnahme der untersuchten Schadstoffe im Vergleich mit einer Kompostzugabe ohne Biokohle beobachtet werden. Bei den verschiedenen Anteilen an Biokohle gab es dann praktisch keine Unterschiede mehr

Enhanced biodegradation of PAHs in historically contaminated soil by M. gilvum inoculated biochar

The inoculation of rice straw biochar with PAH-degrading Mycobacterium gilvum (1.27 × 1011 ± 1.24 × 1010 cell g−1), and the subsequent amendment of this composite material to PAHs contaminated (677 mg kg−1) coke plant soil, was conducted in order to investigate if would enhance PAHs biodegradation in soils. The microbe-biochar composite showed superior degradation capacity for phenanthrene, fluoranthene and pyrene. Phenanthrene loss in the microbe-biochar composite, free cell alone and biochar alone treatments was, respectively, 62.6 ± 3.2%, 47.3 ± 4.1% and non-significant (P > 0.05); whereas for fluoranthene loss it was 52.1 ± 2.3%; non-significant (P > 0.05) and non-significant (P > 0.05); and for pyrene loss it was 62.1 ± 0.9%; 19.7 ± 6.5% and 13.5 ± 2.8%. It was hypothesized that the improved remediation was underpinned by i) biochar enhanced mass transfer of PAHs from the soil to the carbonaceous biochar “sink”, and ii) the subsequent degradation of the PAHs by the immobilized M. gilvum. To test this mechanism, a surfactant (Brij 30; 20 mg g−1 soil), was added to impede PAHs mass transfer to biochar and sorption. The surfactant increased solution phase PAH concentrations and significantly (P < 0.05) reduced PAH degradation in the biochar immobilized M. gilvum treatments; indicating the enhanced degradation occurred between the immobilized M. gilvum and biochar sorbed PAHs

L-DART: A Penetrator Mission for Lunar Permanently Shadowed Regions

Lunar Direct Analysis of Resource Traps (L‐DART) will address many current knowledge gaps concerning lunar volatiles and permanently shadowed regions (PSRs), providing in-situ ground truth data to calibrate numerous existing remote datasets. It builds on UK expertise in developing and testing penetrator system concepts for the Moon and Europa (e.g. MOONLITE). Following release of a Penetrator Descent Module in lunar orbit (Figure 1), its Penetrator Delivery System performs de-orbit and orientation before releasing the instrumented Penetrator to penetrate a few meters into target lunar surface at ~300 m/s. The penetrator itself serves as the sampling tool and an on-board mass spectrometer analyses in-situ the volatiles released both in the impact and in the subsequent thermal soak from lander to surrounding regolith. A pair of 3‐axis accelerometers measure regolith structure during the landing event and constrain penetrator final location. Temperature sensors enable regolith thermal properties to be deduced. Pre-and post impact imagery is obtained for context. Science is complete and data relayed to Earth within 1-2 hours, minimizing system mass and lifetime requirements. Possible landing sites include Cabeus (for comparison with LCROSS) or Shoemaker which exhibits excess hydrogen, or areas indicated by LRO to exhibit putative surface frost. Alternatively, L‐DART could target the hypothesised ancient (paleo) south pole and hence potentially ancient volatiles

Mission Analysis of Robotic Low Thrust Missions to the Martian Moons Deimos And Phobos

The Martian moons Deimos and Phobos are interesting targets for exploration missions, especially within the frame of a crewed Mars orbit mission. To minimize the risk to a crew and also to support EVA site selection, a robotic precursor mission should investigate both moons in advance. The focus of this study is on mission analysis of such a precursor mission that utilizes low-thrust propulsion, in particular Electric Propulsion, for the transfer to the Martian system. We assumed a launch by a Soyuz Fregat in 2018 and a direct injection into an escape trajectory with a hyperbolic excess velocity v∞ = 0 km/s. The spacecraft uses electric propulsion for the interplanetary transfer to Mars and also for spiraling down from an elliptic capture orbit to its destination. The mission analysis comprises dedicated missions to either Deimos or Phobos, and combined missions with Deimos as the primary target and, during a possible mission extension, Phobos as the secondary target. We used two different electric engine types for this study, which represent a wide range of specific impulse Isp. The employed thruster types were the Snecma PPS®1350-G with Isp = 1,650 s and the Astrium RIT-22 in two configurations having Isp = 3,704 s and Isp = 4,763 s. Within the analysis, we varied the number of engines and the available electrical power, followed by a down selection of a system design. In the second part of this study we investigated the implications of transfer time and thruster count on the mission itself caused by permanent degradation of the power and propulsion subsystems. Therefore we selected 15 state vectors of the nominal transfer trajectory and, starting from each of these 15 new initial states, optimized new minimum-duration transfers under the assumption of permanent engine failures or degraded solar cells

Development and Implementation of Automated Image Processing Methods for Verifying Computer-Aided Planning of Intraocular Tumors and a Secure Data Transfer

Die Planung der Bestrahlung intraokularer Tumoren mittels Protonen erfordert ein dreidimensionales Modell des Patientenauges. Das Modell basiert auf Messdaten, die aus Ultraschallaufnahmen und Fundusphotographien gewonnen und während des Aufnähens der Tantal-Clips auf die Sklera des erkrankten Auges gemessen werden. Die Tantal-Clips spielen eine zentrale Rolle bei der Modellierung des Tumors und dienen zur präzisen Positionierung des Patienten während der Bestrahlung. Durch die Verwendung von hochauflösenden Computertomografie (CT) Aufnahmen kann das Augenmodell verifiziert werden. Dies erfordert eine zeitaufwendige manuelle Prozedur und ist nicht in der Planungssoftware implementiert. Der Zeitaufwand für die Verifizierung des Augenmodells konnte durch die Anwendung von automatischen Bildverarbeitungsmethoden reduziert werden. Um diesen Kontrollschritt zu automatisieren, wurde ein 3-D Segmentierungsalgorithmus entwickelt. Hiermit ist die automatische Bestimmung der Clippositionen, die Berechnung der Clipdistanzen und Distanzmessungen im Datensatz möglich. Des Weiteren ist es mit der Software möglich die CT-Daten mit dem Augenmodell zu überlagern. Das Verfahren wurde mittels Phantommessungen evaluiert und bei mehr als 500 Patienten eingesetzt. Die Automatisierung des Verfahrens führte zu einer erheblichen Beschleunigung der Planungsprozedur gegenüber dem herkömmlichen Verfahren mit CT-Filmen. Die CT-Daten werden am Hahn-Meitner-Institut (HMI) Berlin für die Planung und Durchführung der Therapie benötigt. Für den sicheren Transfer der Daten von der Charité - Universitätsmedizin Berlin (Campus Benjamin Franklin) zum HMI über das Internet wurde ein Konzept entwickelt. Die Software verschlüsselt die Daten mit dem Public-Key-Verfahren und transferiert sie dann mit dem File Transfer Protocol (FTP) auf einen für das HMI zugänglichen Server.The planning of proton beam irradiation of intraocular tumors typically requires a 3-dimensional model of the patient’s eye based on measurements taken with ultrasound, fundus photography and during surgery. Tantalum marker clips sutured to the diseased eye’s sclera play a central role in tumor modeling and, during irradiation, in the precise positioning of the patient. Modern high-resolution computed tomography (CT) images may help during the eye modeling. A verification of the eye model with CT data normally entails a time-consuming procedure since this step is not implemented in the standard planning software. The time-consuming procedure of verifying the eye model can be shortened by using automated image processing. To enable such a quality control procedure, a software has been developed that allows the superposition of CT data and eye model, the automatic determination of clip positions, and the calculation of clip-to-clip distances and distance measurements using the CT data. A 3-D segmentation algorithm was developed to automatically segment the volumes of each clip in the CT datasets. The volume center points are used to define the clip positions and to determine the distances between the clips. The process was evaluated using phantom measurements and subsequently applied to more than 500 patients. The planning process was substantially faster than the conventional comparison method using CT film printouts. The Hahn-Meitner- Institut (HMI) Berlin needs the CT data for planning and conducting the therapy. A concept has been developed to transfer the data securely from Charité - Universitätsmedizin Berlin (Campus Benjamin Franklin) to HMI via the internet. The software encrypts the data using the public-key method and subsequently transfers the data using the file transfer protocol (FTP) to a server which can be accessed by the HMI

Mikrobieller Abbau von 14C-markiertem Pyren und Benzo[a]pyren durch eine erstmals beschriebene Mycobacterium-Spezies

Pyrene and benzo[a]pyrene belonging to the class of polycyclic aromatic hydrocarbons (PAHs) are of concern for both human health and the environment due to their mutagenicity, carcinogenicity and persistence. The present thesis deals with the microbial degradation of pyrene and benzo[a]pyrene by bacterial pure cultures. A total of 104 different microbial strains were isolated from a PAH-degrading bacterial mixed culture, but only 12 strains turned out to be PAH-degraders. The most effective strains 17A3 and 4IIb were chosen, characterized and used in degradation experiments. The pure culture of 17A3 was identified as a new member of the genus Mycobacterium which was not described before. In order to compare strain 17A3 to strain 4IIb on the DNA level, 16S-23S-rDNA-Intergenic-Spacer-Amplification (RISA) was conducted indicating that both strains are belonging to the same species. Degradation experiments were carried out with both non-labelled and radiolabelled pyrene and benzo[a]pyrene, respectively in order to quantify reliably the degradation and to detect radiolabelled metabolites. Strains 17A3 and 4IIb were able to use pyrene as sole source of carbon and energy and converted pyrene completely into carbon dioxide, metabolites and biomass. Metabolites detected in the culture medium were identified as far as possible by means of radio-TLC, HPLC and GC-MS analysis and correspond to the degradation pathways described in the literature. Dimethoxy-pyrene was identified as an additional metabolite formed from pyrene. In contrast, both strains cannot use benzo[a]pyrene for growth. Degradation studies of benzo[a]pyrene were therefore carried out in presence of pyrene. Benzo[a]pyrene was mineralized at this cometabolic conditions only to a minor extent (up to 2% of applied benzo[a]pyrene). Nevertheless, it was demonstrated that strain 17A3 was able to convert benzo[a]pyrene almost completely into more polar metabolites. Due to the special 12C:14C isotope ratio of the applied radiolabelled benzo[a]pyrene, metabolites can be differed from matrix substances and can be attributed reliably to the parent compound. Metabolites were identified as far as possible by the mass spectra indicating two different benzo[a]pyrene-dihydrodiols and two ring fission products like chrysene-dicarboxylic acid and hydroxy-methoxy-chrysene. The degradation of pyrene and benzo[a]pyrene in a mixture was influenced reciprocally by each other: Mineralisation of benzo[a]pyrene ceased if pyrene was depleted and increased if pyrene was added. The degradation rate of benzo[a]pyrene cannot be increased with increasing benzo[a]pyrene concentration. Furthermore, the degradation rates of pyrene decreased if benzo[a]pyrene was present. A toxic effect of benzo[a]pyrene on the degrading microorganisms could not be shown. However, it could not be excluded by means of the performed experiments

Mikrobieller Abbau von 14C-markiertem Pyren und Benzo[a]pyren durch eine erstmals beschriebene Mycobacterium-Spezies

Pyrene and benzo[a]pyrene belonging to the class of polycyclic aromatic hydrocarbons (PAHs) are of concern for both human health and the environment due to their mutagenicity, carcinogenicity and persistence. The present thesis deals with the microbial degradation of pyrene and benzo[a]pyrene by bacterial pure cultures. A total of 104 different microbial strains were isolated from a PAH-degrading bacterial mixed culture, but only 12 strains turned out to be PAH-degraders. The most effective strains 17A3 and 4IIb were chosen, characterized and used in degradation experiments. The pure culture of 17A3 was identified as a new member of the genus Mycobacterium which was not described before. In order to compare strain 17A3 to strain 4IIb on the DNA level, 16S-23S-rDNA-Intergenic-Spacer-Amplification (RISA) was conducted indicating that both strains are belonging to the same species. Degradation experiments were carried out with both non-labelled and radiolabelled pyrene and benzo[a]pyrene, respectively in order to quantify reliably the degradation and to detect radiolabelled metabolites. Strains 17A3 and 4IIb were able to use pyrene as sole source of carbon and energy and converted pyrene completely into carbon dioxide, metabolites and biomass. Metabolites detected in the culture medium were identified as far as possible by means of radio-TLC, HPLC and GC-MS analysis and correspond to the degradation pathways described in the literature. Dimethoxy-pyrene was identified as an additional metabolite formed from pyrene. In contrast, both strains cannot use benzo[a]pyrene for growth. Degradation studies of benzo[a]pyrene were therefore carried out in presence of pyrene. Benzo[a]pyrene was mineralized at this cometabolic conditions only to a minor extent (up to 2% of applied benzo[a]pyrene). Nevertheless, it was demonstrated that strain 17A3 was able to convert benzo[a]pyrene almost completely into more polar metabolites. Due to the special 12C:14C isotope ratio of the applied radiolabelled benzo[a]pyrene, metabolites can be differed from matrix substances and can be attributed reliably to the parent compound. Metabolites were identified as far as possible by the mass spectra indicating two different benzo[a]pyrene-dihydrodiols and two ring fission products like chrysene-dicarboxylic acid and hydroxy-methoxy-chrysene. The degradation of pyrene and benzo[a]pyrene in a mixture was influenced reciprocally by each other: Mineralisation of benzo[a]pyrene ceased if pyrene was depleted and increased if pyrene was added. The degradation rate of benzo[a]pyrene cannot be increased with increasing benzo[a]pyrene concentration. Furthermore, the degradation rates of pyrene decreased if benzo[a]pyrene was present. A toxic effect of benzo[a]pyrene on the degrading microorganisms could not be shown. However, it could not be excluded by means of the performed experiments