Diagnostic System of Coronary Artery Disease: Parameter Identification Tasks and Treatment of Tracer Kinetic Problems by using Integral Equations

We will deal with the development of a computer system within the framework of the newly-established “AUSTRIAN GRID” for patient-specific simulation studies of the flow of blood in the entire coronary circulation. The properties of the intramyocardial vessels must be deduced from PET perfusion images by means of large-scale parameter identification methods. The tracer kinetic parameters can be efficiently be identified by solving integral equations. We will point out the details of the parameter identification tasks and especially the treatment of tracer kinetic problems by using integral equations. [DOI: 10.1685/CSC06128] About DO

Sodium 2-mercaptoethanesulfonate monohydrate (coenzyme M sodium salt monohydrate)

The 2-thio­ethanesulfonate anion is the smallest known coenzyme in nature (HS–CoM) and plays a key role in methano­genesis by anaerobic archaea, as well as in the oxidation of alkenes by Gram-negative and Gram-positive eubacteria. The title compound, Na+·C2H5O3S2 −·H2O, is the Na+ salt of HS–CoM crystallized as the monohydrate. Six O atoms form a distorted octa­hedral coordination geometry around the Na atom, at distances in the range 2.312 (4)–2.517 (3) Å. Two O atoms of the sulfonate group, one O atom of each of three other symmetry-related sulfonate groups plus the water O atom form the coordination environment of the Na+ ion. This arrangement forms Na–O–Na layers in the crystal structure, parallel to (100)

Additions of carbenium ions to nonconjugated dienes. The retarding (−I)-effect of the second double bond.

Kinetics for the addition of the p-methoxybenzhydryl cation (AnPhCH+, 10) towards nonconjugated dienes 11 [H2C=C(CH3)-(CH2)n-C(CH3)=CH2] have been determined in CH2Cl2 at −30° to −70°C. Reactivity increases with increasing number of methylene groups separating the two double bonds. For N = 4, reactivity reaches the value for saturated alkyl substituents, and nucleophilic assistance of the second double bond is never observed

Aerobic Oxidation of Cyclohexane Catalyzed by Flame-Made Nano-Structured Co/SiO2 Materials

The aerobic oxidation of cyclohexane was studied at 130°C in the presence of a Co/SiO2 catalyst, synthesized by flame-spray pyrolysis. Characterization of the material indicates that at low Co-loadings, CoII is predominantly present as tetrahedral species, whereas at higher loadings also small amounts of octahedral species can be found at the surface of the agglomerated nano-particles. Catalytic experiments demonstrate high activity, causing a complete in situ deperoxidation of the intermediate cyclohexylhydroperoxide. Hot-separation and catalyst-recycle tests corroborate the heterogeneous nature of the catalys

Monitoring of metabolic parameters of mammal cells cultures in microfluidic devices using integrated optical chemical sensors

Optical chemical sensors are well established in the chemical industry, life science, biotechnology and research laboratories. They are operate non-invasive, do not need any reference elements and can be read-out via contactless measurement. Moreover, it is possible to miniaturize and integrate them into microfluidic systems. Due to their simple composition, optical sensors can be produced at low price and therefore represent a good alternative compared to electrochemical sensors for their application in disposable microfluidics. The various possibilities of integrated optical oxygen sensors have already shown their potential in different microfluidic applications [1]. However, monitoring of further metabolic parameters is important for a better understanding of biological processes. Therefore, our group develops, next to oxygen sensors, also optical sensors for monitoring pH, glucose, CO2, ammonia and various ions. Still, integration in a Lab-on-a-chip format is a challenging task due to the state-of-the-art performances in terms of signal brightness, response times, optoelectronic read-out systems, fabrication and integration. Please click Additional Files below to see the full abstrac

Dynamic Power Management for Neuromorphic Many-Core Systems

This work presents a dynamic power management architecture for neuromorphic many core systems such as SpiNNaker. A fast dynamic voltage and frequency scaling (DVFS) technique is presented which allows the processing elements (PE) to change their supply voltage and clock frequency individually and autonomously within less than 100 ns. This is employed by the neuromorphic simulation software flow, which defines the performance level (PL) of the PE based on the actual workload within each simulation cycle. A test chip in 28 nm SLP CMOS technology has been implemented. It includes 4 PEs which can be scaled from 0.7 V to 1.0 V with frequencies from 125 MHz to 500 MHz at three distinct PLs. By measurement of three neuromorphic benchmarks it is shown that the total PE power consumption can be reduced by 75%, with 80% baseline power reduction and a 50% reduction of energy per neuron and synapse computation, all while maintaining temporary peak system performance to achieve biological real-time operation of the system. A numerical model of this power management model is derived which allows DVFS architecture exploration for neuromorphics. The proposed technique is to be used for the second generation SpiNNaker neuromorphic many core system

Coordination and binding geometry of methyl-coenzyme M in the red1m state of methyl-coenzyme M reductase

Methane formation in methanogenic Archaea is catalyzed by methyl-coenzyme M reductase (MCR) and takes place via the reduction of methyl-coenzyme M (CH3-S-CoM) with coenzyme B (HS-CoB) to methane and the heterodisulfide CoM-S-S-CoB. MCR harbors the nickel porphyrinoid coenzyme F430 as a prosthetic group, which has to be in the Ni(I) oxidation state for the enzyme to be active. To date no intermediates in the catalytic cycle of MCRred1 (red for reduced Ni) have been identified. Here, we report a detailed characterization of MCRred1m ("m” for methyl-coenzyme M), which is the complex of MCRred1a ("a” for absence of substrate) with CH3-S-CoM. Using continuous-wave and pulse electron paramagnetic resonance spectroscopy in combination with selective isotope labeling (13C and 2H) of CH3-S-CoM, it is shown that CH3-S-CoM binds in the active site of MCR such that its thioether sulfur is weakly coordinated to the Ni(I) of F430. The complex is stable until the addition of the second substrate, HS-CoB. Results from EPR spectroscopy, along with quantum mechanical calculations, are used to characterize the electronic and geometric structure of this complex, which can be regarded as the first intermediate in the catalytic mechanis