Fundamental dynamics of flow through carbon nanotube membranes

The flow of a model non-polar liquid through small carbon nanotubes is studied using non-equilibrium molecular dynamics simulation. We explain how a membrane of small-diameter nanotubes can transport this liquid faster than a membrane consisting of larger-diameter nanotubes. This effect is shown to be back-pressure dependent, and the reasons for this are explored. The flow through the very smallest nanotubes is shown to depend strongly on the depth of the potential inside, suggesting atomic separation can be based on carbon interaction strength as well as physical size. Finally, we demonstrate how increasing the back-pressure can counter-intuitively result in lower exit velocities from a nanotube. Such studies are crucial for optimisation of nanotube membranes.     

Treiber der Adoption SaaS-basierter Anwendungen

Software-as-a-Service (SaaS) is said to become an important cornerstone of the Internet of Services. However, while some market research and IT provider firms fervently support this point of view, others already conjure up the failure of this on-demand sourcing option. Oftentimes based on weak empirical data and shaky reasoning, these inconsistent perspectives lack scientific rigor and neglect to present a more differentiated picture of SaaS-adoption. This study seeks to deepen the understanding of factors driving the adoption of Software-as-a-Service (SaaS). Grounded in transaction cost theory, the resource-based view, and the theory of planned behavior, the authors develop a research model to assess SaaS-adoption at the application level. Survey data of 297 firms in Germany with 374 valid response items across different industries were collected to test the theoretical model. Our analysis revealed that patterns of the decision on SaaS-adoption differ across application types. Social influence, attitude toward SaaS-adoption, adoption uncertainty, and strategic value turned out to be the strongest and most consistent drivers across all application types. Furthermore, it was found that firm size does not matter in SaaS-adoption, since large enterprises and small- and medium-sized companies had similar adoptation rates. Overall, this study provides relevant findings that IT vendors can use to better appeal to potential companies that consider adopting SaaS.     

Fast transmission CT for determining attenuation maps using a collimated line source, rotatable air-copper-lead attenuators and fan-beam collimation

We describe a technique using a line source and a rotatable air-copper-lead assembly to acquire gamma transmission computed tomographic (TCT) data for determining attenuation maps to compensate SPECT emission scans. The technique minimizes problems associated with discriminating 99mTc transmission and 201Tl emission photons and requires only a modest increase in total study time. A 99mTc line source and a stacked foil ("multislat") collimator are placed near the focal line of a fan-beam collimator (114 cm focal length) mounted on one detector of a triple-camera SPECT system. We acquired TCT data of plastic rod and anthropomorphic thorax phantoms to investigate the capability of the line source and rotatable air-copper-lead attenuators to determine attenuation maps. The data were acquired with and without 5.4 MBq (145 microCi) of 201Tl placed in the myocardial chamber of the thorax phantom. Phantoms also were scanned using a curved transmission slab source mounted to a parallel-hole collimator. Fan-beam TCT images have improved resolution compared with parallel-beam TCT images. Two patient scans also were performed to evaluate the clinical usefulness of fan-beam TCT. The rotatable air-copper-lead attenuator method eliminates contamination of emission data by transmission photons and reduces spill-over of emission data into the transmission energy window for some cases. Results show the feasibility of using fast, sequential or interlaced transmission scans of a line source within a rotatable air-copper-lead attenuator assembly to obtain accurate attenuation maps for SPECT attenuation compensation.     

Observations of quantized vorticity generated in superfluid 4He flow through 2-Μm-diameter orifices

A beam of charged vortex rings is used to study the vorticity present downstream from an array of 2-m-diameter orifices through which a steady flow of superfluid ⁴He is driven at known velocity and pressure head p. From the measured attentuation of the beam at low p, we infer a density of vortex line less than predicted by the Feynman critical velocity model. Possible explanations are considered. We find evidence that an interconnected tangle of vortices is formed above a certain value of p, which is in reasonable agreement with theory, at least for one orifice plate. Charge transfer and transient attenuation measurements indicate that this tangle decays in part into small vortex rings. These results are compared with an earlier experiment of Gamota.Research supported in part by the National Science Foundation under grant DMR 72-02971.     

In-house and interlaboratory validation of a method for the extraction of DNA from maize starch

Here, we describe the procedure of a DNA extraction method from maize starch including the method??s validation by in-house and interlaboratory tests. The amplifiable amount of maize DNA tested by real-time PCR was used as parameter for evaluating our method. The practical (i.e. relative) limit of detection (LOD) was used as key criterion for assessing the suitability of the extraction method with respect to genetically modified organism analysis. In a round-robin test with ten participating laboratories, satisfactory results were achieved with practical LODs in the range of 0.1?% with three native maize starch materials. In-house tests showed that this protocol??with an additional purification step??can also be applied for extracting DNA from chemically or enzymatically modified starch.     

Der Verdacht der Simulation

The Suspicion of Simulation. A Psychiatric Case History between Appropriation and Disciplinary Action at the End of the 19th Century. This case history explores how the question of agency was dealt with historically in two developing, normative orders of deviant behaviour. Examining the institutional career of the supposed adulterer, marriage swindler, and craft baker, we can trace the different observation regimes and systems of knowledge acquisition in the prison and in psychiatry. In both institutions there was talk of simulated madness; the explanations, however, were different. For the prison doctors and civil servants, the baker was a criminal; his deviant behaviour was a matter of consciously planned-out deception. For the examining psychiatrist, on the other hand, he was mentally ill and could not be held responsible for his own behaviour.     

Elektrochemische Adamantylierung von reduktiv dehalogenierbaren Chinolinen

Electrolytic Adamantylation by Reductive Coupling of Quinolinylhalides in the Presence of 1-Bromoadamantane Electrochemically generated anion radicals of a number of halogen-substituted quinolines 1 a–g dehalogenate in N,N-dimethylformamide to halogen anions and radicals, which may stabilize by hydrogen abstraction from the solvent. In the presence of 1-bromoadamantane the fragments of reductive dehalogenation may be used synthetically for indirect generation of 1-bromoadamantane-radicals, which react predominantly to cross-coupled 2- and 7-monoadamantylated dihydroquinoline- and quinoline-structures, independent of the original halogen position. If C-2 is blocked, adamantylation takes place in the carbocyclic ring. Product distribution and cyclic-voltammetric results are discussed in terms of mechanism.