X-ray and NMR spectroscopic characterisation of cyclic titanodiphenylsiloxanes and examination of the hydrolytic stability of their Si-O-Ti bonds

Six crystalline titanodiphenylsiloxanes have been synthesised by reaction of diphenylsilanediol (DPSD) with titanium tetraisopropoxide or its complexes with acetylacetonate (acac) as ligand. Two of them show a spirocyclic structure with the formula TiO2[O2Si2(C6H5)(4)](2) A and TiO2[O4Si4(C6H5)(8)](2) B which have already been described in the literature. Two compounds C and D were identified by X-ray analysis to have the same bicyclic structure but different coordinating solvent molecules. Tetrahydrofuran acts as a non-bridging ligand at the Ti atoms in [Ti(acac)0(1.5)](2)[OSi(C6H5)(2)](3)?2C(4)H(8)O C while dioxane acts as a bridging ligand between the Ti atoms of neighbouring molecules of [Ti(acac)O-1.5](2)[OSi(C6H5)(2)](3)?3C(4)H(8)O(2) D. The titanodiphenylsiloxanes E and F were identified by a cyclotetrameric structure and the formulas [Ti(acac)(2)O](2)[OSi(C6H5)(2)](2) and [Ti(acac)(2)O][OSi(C6H5)(2)](3), respectively. The titanodiphenylsiloxanes A-E were characterised by Si-29 and O-17 NMR spectroscopy, IR and time-of-flight mass spectrometry measurements. The hydrolytic stabilities of the Si-O-Ti bonds in the titanodiphenylsiloxanes A-E have been examined mainly by means of Si-29 NMR spectroscopy. The results reveal a strong influence of the structure type of the titanodiphenylsiloxanes on the hydrolytic stability of their Si-O-Ti bonds apart from the hydrolytic conditions (amount of water, Si, Ti and H+ concentration). The hydrolytic stability of the titanodiphenylsiloxanes A-E decreases in the order cyclotetramer (E)> spirocyclo (A, B)> bicycle (C, D). Reasons for the different hydrolytic stability are discussed. The results on the different hydrolytic stabilities of Si-O-Ti bonds can contribute to a better understanding of the synthesis of homogeneous heterometal materials on a molecular scale via the sol-gel process

Construction of an optical test-bed for eLISA

In the planned eLISA mission a key part of the system is the optical bench that holds the interferometers for reading out the inter-spacecraft distance and the test mass position. We report on ongoing technology development for the eLISA optical system like the back-link between the optical benches and the science interferometer where the local beam is interfered with the received beam from the distant spacecraft. The focus will be on a setup to investigate the tilt-to-pathlength coupling in the science interferometer. To test the science interferometer in the lab a second bench providing a laser beam and a reference interferometer is needed. We present a setup with two ultra-stable low expansion glass benches and bonded optics. To suppress the tilt-to-pathlength coupling to the required level (few μm/rad) imaging optics are placed in front of the interferometer photo diodes

Detecting Malicious Code by Model Checking

Abstract. The ease of compiling malicious code from source code in higher programming languages has increased the volatility of malicious programs: The first appearance of a new worm in the wild is usually followed by modified versions in quick succession. As demonstrated by Christodorescu and Jha, however, classical detection software relies on static patterns, and is easily outsmarted. In this paper, we present a flexible method to detect malicious code patterns in executables by model checking. While model checking was originally developed to verify the correctness of systems against specifications, we argue that it lends itself equally well to the specification of malicious code patterns. To this end, we introduce the specification language CTPL (Computation Tree Predicate Logic) which extends the well-known logic CTL, and describe an efficient model checking algorithm. Our practical experiments demonstrate that we are able to detect a large number of worm variants with a single specification. Key words: Model Checking, Malware Detection.

Classification of Chimney EVAR-Related Endoleaks: Insights from the PERICLES Registry

Juxtarenal aortic aneurysms (JAAs) pose significant challenges for endovascular aneurysm repair (EVAR). A short or absent infrarenal neck typically excludes standard EVAR as a viable or reasonable treatment option. In this context, the use of chimney grafts (chEVAR) is gaining in popularity and applicability. These grafts are designed to course in the aortic lumen outside the main stent-graft to maintain normal perfusion to the involved target branches. As such, they may represent a promising and less resource-intensive option for management of JAAs. However, this technical strategy is not without challenges of its own, particularly the inevitable creation of \u201cgutters\u201d that result from the interaction of the chimney graft with the main aortic stent-graft. These gutters can become a conduit for type Ia endoleak formation, hence they represent the Achilles\u2019 heel of chEVAR. Current reports point to a relatively wide-ranging incidence (0%\u201313%) of type Ia endoleaks related to chEVAR. The PERICLES Registry collected the global transatlantic experience of 13 European and US vascular centers reporting 517 patients with complex aneurysms treated with EVAR and chimney parallel grafts. Overall, 6% of PERICLES chEVAR patients had a type Ia endoleak at completion angiography, but the rate of persistent endoleaks was only 2.9% at a mean 17.1 months of follow-up. Close review of the postoperative computed tomography angiograms of these persistent endoleak patients revealed distinct types and patterns of chEVAR-related type Ia endoleaks and form the basis of a new classification proposed herein. It is hoped that these observations will lead to development of new treatment algorithms for effective management of chimney-related endoleaks and, in some cases, to prevent them from occurring in the first place

The bicoid mRNA localization factor Exuperantia is an RNA-binding pseudonuclease.

This is the author accepted manuscript.Final version available from Nature Research via the DOI in this record.Anterior patterning in Drosophila is mediated by the localization of bicoid (bcd) mRNA at the anterior pole of the oocyte. Exuperantia (Exu) is a putative exonuclease (EXO) associated with bcd and required for its localization. We present the crystal structure of Exu, which reveals a dimeric assembly with each monomer consisting of a 3'-5' EXO-like domain and a sterile alpha motif (SAM)-like domain. The catalytic site is degenerate and inactive. Instead, the EXO-like domain mediates dimerization and RNA binding. We show that Exu binds RNA directly in vitro, that the SAM-like domain is required for RNA binding activity and that Exu binds a structured element present in the bcd 3' untranslated region with high affinity. Through structure-guided mutagenesis, we show that Exu dimerization is essential for bcd localization. Our data demonstrate that Exu is a noncanonical RNA-binding protein with EXO-SAM-like domain architecture that interacts with its target RNA as a homodimer.This project received funding from the Max Planck Gesellschaft, the European Research Council under the European Union's Seventh Framework Programme (FP7/2007-2013), ERC grant agreement no. 310957 and the Deutsche Forschungsgemeinschaft (SFB860 to K.K. and H.U., and BO3588/2-1 to F.B.)

RS12. Sustained Late Branch Patency and Low Incidence of Persistent Type Ia Endoleaks Following Snorkel/chimney EVAR Shown in the Updated PERICLES Registry

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Collected world experience about the performance of the snorkel/chimney endovascular technique in the treatment of complex aortic pathologies: The PERICLES registry

Objectives: We sought to analyze the collected worldwide experience with use of snorkel/chimney endovascular aneurysm repair (EVAR) for complex abdominal aneurysm treatment. Background: EVAR has largely replaced open surgery worldwide for anatomically suitable aortic aneurysms. Lack of availability of fenestrated and branched devices has encouraged an alternative strategy utilizing parallel or snorkel/chimney grafts (ch-EVAR). Methods: Clinical and radiographic information was retrospectively reviewed and analyzed on 517 patients treated by ch-EVAR from 2008 from 2014 by prearranged defined and documented protocols. Results: A total of 119 patients in US centers and 398 in European centers were treated during the study period. US centers preferentially used Zenith stent-grafts (54.2%) and European centers Endurant stent-grafts (62.2%) for the main body component. Overall 898 chimney grafts (49.2% balloon expandable, 39.6% self-expanding covered stents, and 11.2% balloon expandable bare metal stents) were placed in 692 renal arteries, 156 superior mesenteric arteries (SMA), and 50 celiac arteries. At a mean follow-up of 17.1 months (range: 1-70 months), primary patency was 94%, with secondary patency of 95.3%. Overall survival of patients in this high-risk cohort for open repair at latest follow-up was 79%. Conclusions: This global experience represents the largest series in the ch-EVAR literature and demonstrates comparable outcomes to those in published reports of branched/fenestrated devices, suggesting the appropriateness of broader applicability and the need for continued careful surveillance. These results support ch-EVAR as a valid off-the-shelf and immediately available alternative in the treatment of complex abdominal EVAR and provide impetus for the standardization of these techniques in the future