Kaspar Bütikofer, Der frühe Zürcher Pietismus (1689–1721), 2009

No abstract available

Darstellung und Eigenschaften von cyclo-Nonaschwefeloxid (S9O) und von cyclo-Dekaschwefeloxid (S10O) [1] / Preparation and Properties of cyclo-Nonasulfuroxide (S9O) and of cyclo-Decasulfuroxide (S10O) [1]

The homocyclic oxides S9O (m.p. 33 °C, dec.) and S10O (m.p. 51 °C, dec.) have been prepared by oxidation of the corresponding sulfur rings S9 and S10 , respectively, by trifluoroperoxy acetic acid (molar ratio 1:2-3) in a carbon disulfide/methylene chloride mixture. According to infrared and Raman spectra, both compounds contain an exocyclic oxygen atom. S9O and S10O decompose at 25 °C to give SO2 and a polysulfuroxide SnO with >10 but both can be stored at -78 °C without decomposition. The SS bond distances are discussed on the basis of the Raman spectra. In addition, the Raman spectrum of solid S9 has been recorded for the first time. It shows that S9 crystallizes as two allotropes (α-and β-S9) both consisting of cyclic molecules of either C1 or C2 symmetry with bond distances of between 203 and 209 pm

Resolution uniformity and sensitivity of the NIH ATLAS small animal PET scanner: comparison to simulated LSO scanners without depth-of-interaction capability

Proceeding of: 2001 Nuclear Science Symposium and Medical Imaging Conference, november 4-10, 2001, San Diego, CaliforniaPET scanners designed to image animals the size of rats and mice should possess simultaneously high and uniform spatial resolution and high sensitivity. ATLAS (Advanced Technology Laboratory Animal Scanner), an 11.8 cm diameter aperture, 2 cm axial field-of-view ring-type research scanner seeks these goals by surrounding the animal with eighteen 15 mm deep, LGSO (7 mm) / GSO (8 mm) phoswich detector modules. A Monte Carlo simulation was used to compare the variation of resolution across the field-of-view and the absolute central point source sensitivity (ACS) of ATLAS to similar systems comprised only of LSO arrays of different depths with no depth-of-interaction (DOI) capability. For ATLAS radial spatial resolution deteriorated by 27% from the center to 3 cm off-axis. Scanners comprised of 15 mm deep, 10 mm deep and 7 mm deep LSO crystals deteriorated by 100%, 51%, and 20% respectively, over the same distance. Simulated ACS (absorbed energies > 250 keV) for ATLAS was 2.0% and for the 15 mm, 10 mm deep and 7 mm deep LSO scanners 2.4%, 1.5%, and 0.9%, respectively. Radial resolution loss 3 cm off-axis and ACS measured for the actual ATLAS scanner were similar to the values obtained by simulation (27% resolution loss, 1.8% ACS). The phoswich design thus achieves good resolution uniformity over a 6 cm FOV while preserving sensitivity compared to equivalent non-DOI LSO scanners with a range of crystal depths.Publicad

A depth-encoding PET detector module with improved spatial sampling

Proceeding of: 1998 IEEE Nuclear Science Symposium and Medical Imaging Conference, Toronto, Ont., 08 - 14 Nov. 1998Detector modules in small ring diameter PET scanners must possess depth-of-interaction (DOI) encoding, increased spatial sampling, high sensitivity and the ability to handle high photon input rates without excessive pulse pileup or random coincidences. We created such a module by optically coupling an entrance array of individual LGSO crystals to an exit array of individual GSO (and other) crystals that was, in turn, optically and directly coupled to a miniature PSPMT. DO1 was determined for each event by delayed charge integration (DCI), a technique that exploits differences in light decay time between GSO and LGSO. Spatial sampling in 3D was increased by introducing a half crystal pitch spatial offset between the entrance and exit arrays in both the X and Y directions. Position detection accuracy in both the LGSO and GSO layers, and the accuracy of DO1 assignment of events to either layer was high. These results suggest that this combination of scintillators and acquisition/processing methods may be particularly useful in the design of high performance, small ring diameter PET scanners for small animal imagingPublicad

Redetermination of cyclo-tetra­kis­(μ-5,10,15,20-tetra-4-pyridyl­porphyrinato)tetra­zinc(II) dimethyl­formamide octa­solvate trihydrate at 100 K

The structure of the title compound, [Zn4(C40H24N8)4]·8C3H7NO·3H2O, has been redetermined at 100 K. The redetermination is of significantly higher precision and gives further insight into the disorder of pyridyl groups and solvent mol­ecules. The mol­ecules of (5,10,15,20-tetra-4-pyridyl­porphyrinato)zinc(II) (ZnTPyP) form homomolecular cyclic tetra­mers by coordination of a peripheral pyridyl group to the central Zn atom of an adjacent symmetry-related mol­ecule. The tetra­mer so formed exhibits mol­ecular S 4 symmetry and is located about a crystallographic fourfold rotoinversion axis. Severely disordered dimethyl­formamide and water mol­ecules are present in the crystal, the contributions of which were omitted from refinement. Inter­molecular C—H⋯N hydrogen bonding is observed

Corrigendum: Kinetic studies and CFD-based reaction modeling for insights into the scalability of ADC conjugation reactions

The manufacturing of antibody-drug conjugates (ADCs) involves the addition of a cytotoxic small-molecule linker-drug (= payload) to a solution of functionalized antibodies. For the development of robust conjugation processes, initially small-scale reaction tubes are used which requires a lot of manual handling. Scale-up to larger reaction vessels is often knowledge-driven and scale-comparability is solely assessed based on final product quality which does not account for the dynamics of the reaction. In addition, information about the influence of process parameters, such as stirrer speed, temperature, or payload addition rates, is limited due to high material costs. Given these limitations, there is a need for a modeling-based approach to investigate conjugation scale-up. In this work, both experimental kinetic studies and computational fluid dynamics (CFD) conjugation simulations were performed to understand the influence of scale and mixing parameters. In the experimental part, conjugation kinetics in small-scale reaction tubes with different mixing types were investigated for two ADC systems and compared to larger bench-scale reactions. It was demonstrated that more robust kinetics can be achieved through internal stirrer mixing instead of external mixing devices, such as orbital shakers. In the simulation part, 3D-reactor models were created by coupling CFD-models for three large-scale reaction vessels with a kinetic model for a site-specific conjugation reaction. This enabled to study the kinetics in different vessels, as well as the effect of process parameter variations in silico. Overall, it was found that for this conjugation type sufficient mixing can be achieved at all scales and the studied parameters cause only deviations during the payload addition period. An additional time-scale analysis demonstrated to aid the assessment of mixing effects during ADC process scale-up when mixing times and kinetic rates are known. In summary, this work highlights the benefit of kinetic models for enhanced conjugation process understanding without the need for large-scale experiments.</p

A high performance prhoswich detector module for small animal PET

Proceeding of: 47th Annual Meeting Society of Nuclear Medicine, , St. Louis, MO, USA, June 3-7, 200