Reaktion des Jodats mit Bromidionen in der eutektischen Schmelze des Lithium- und Kaliumbromids

Ohne Zusammenfassung     

Photometrische Bestimmung kleiner Phosphatmengen mit Malachitgrün

In the presence of a stabilising colloid Malachite Green and phosphododekamolybdate acid form a dyestuff salt. When the excess of the Malachite Green has reacted in acid solution to colourless products, the remaining colour is a measure for the phosphate quantity. The method permits the determination of 10–1200 μg of phosphate/l.     

Rheologie pathologischer Gelenkflüssigkeiten

Zusammenfassung Mit Hilfe des Weissenberg-Rheogoniometers wurden an 107 pathologischen Kniegelenkspunktaten (47 nicht entzündliche, 60 entzündliche) das viskose Fließverhalten, Normalkräfte und anhand von Anlaufmessungen ein Schermodul zur Berechnung der Anzahl molekularer Verhängungen bestimmt. Viskoses und elastisches Verhalten der entzündlichen Gelenkergüsse unterscheiden sich zwar deutlich von dem der nichtentzündlichen Ergüsse, die hohe Streuung der Werte weist jedoch darauf hin, daß verschiedene pathogenetische Vorgänge zu den gleichen rheologischen Eigenschaften der Synovia führen können. Daher ist der differentialdiagnostische Aussagewert der rheologischen Untersuchungsergebnisse gering.Hyaluronsäure-Konzentrationsänderungen sind nur zum Teil für die pathologische Rheologie der Synovia verantwortlich. Die Anwendung einer Normierungsmethode auf die Viskosität der Synovia läßt Unterschiede im Polymerisationsgrad der Hyaluronsäure in entzündlichen und nicht entzündlichen Ergüssen erkennen.

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Summary In 107 pathological synovial fluid samples of knee joints (47 non-inflammatory, 60 inflammatory) the Weissenberg-Rheogoniometer is used for measurements of viscosity, normal force and a shear modulus obtained by prestationary measurements to calculate the number of molecular entanglements.Viscosity and elasticity of the inflammatory synovial fluids are clearly different from the non-inflammatory group, but the high scattering of the values shows that various pathological conditions lead to the same rheological properties of the synovial fluid. Therefore the rheological results have little diagnostic signification.Variation of the hyaluronic acid concentrations are responsible only in part for the pathological synovial fluid rheology. A normalization method for the synovial fluid viscosity suggests differences in the polymerisation of the hyaluronic acid in inflammatory and non-inflammatory synovial fluids.

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Mit 6 Abbildungen und 1 Tabelle     

Effect of magnetic doping on the electronic states of Ni

Angle-resolved photoemission is used to determine the change in the electronic states of Ni induced by doping with Fe and Cr. Well-defined spin and k states are selected using high energy and k resolution combined with single crystal alloys. Iron suppresses the mean free path of minority spins only, while chromium suppresses both spins and decreases the magnetic splitting. The strong variation of these effects from one impurity to the other supports the concept of magnetic doping.     

Identifying Trends in Word Frequency Dynamics

The word-stock of a language is a complex dynamical system in which words can be created, evolve, and become extinct. Even more dynamic are the short-term fluctuations in word usage by individuals in a population. Building on the recent demonstration that word niche is a strong determinant of future rise or fall in word frequency, here we introduce a model that allows us to distinguish persistent from temporary increases in frequency. Our model is illustrated using a 10⁸-word database from an online discussion group and a 10¹¹-word collection of digitized books. The model reveals a strong relation between changes in word dissemination and changes in frequency. Aside from their implications for short-term word frequency dynamics, these observations are potentially important for language evolution as new words must survive in the short term in order to survive in the long term.     

Total Synthesis and Biological Assessment of Mandelalide A

A new convergent total synthesis of the marine macrolide mandelalide A ( 1 ) has been developed that is based on macrocyclic ring closure by a Shiina‐type macrolactonization and the construction of the requisite precursor seco acid by a highly efficient Sonogashira cross‐coupling reaction between two fragments of comparable complexity. Key steps in the elaboration of the acid building block were the enantioselective, catalytic addition of a protected acetylene to crotonaldehyde and the construction of the tetrahydropyran unit that is embedded in the macrocycle by means of an acid‐catalyzed Prins reaction. The synthesis of the alcohol fragment features the formation of the trisubstituted tetrahydrofuran ring through an acetal cleavage/epoxide opening cascade reaction and a rarely used radical alkynylation of a primary alkyl iodide. Intriguingly, the dihydroxylation of a terminal double bond as part of the synthesis of this building block gave the same major product for both the α‐ and β‐AD‐mix reagents, albeit with moderate or low selectivity. Synthetic mandelalide A ( 1 ) was a potent proliferation inhibitor of A549, HT460, and H1299 human lung cancer cells in vitro, but not of SK‐N‐SH neuroblastoma cells. However, in no case did we observe complete cell kill even at the highest compound concentration tested (5 μm ).     

Stress analysis by combination of holographic interferometry and boundary-integral method

The paper describes a hybrid experimental and numerical method analysis of bodies. It consists of the experimental method of double-aperture speckle interferometry and the boundary-integral method. The interference patterns allowing evaluation of the displacement vector are obtained by the speckle interferometry. The boundary displacements obtained experimentally are conveniently used for the calculation of stresses in the body by the boundary-integral method. Some examples bear witness of the effectiveness and accuracy of the hybrid technique.