Data analysis procedures for pulse ELDOR measurements of broad distance distributions

The reliability of procedures for extracting the distance distribution between spins from the dipolar evolution function is studied with particular emphasis on broad distributions. A new numerically stable procedure for fitting distance distributions with polynomial interpolation between sampling points is introduced and compared to Tikhonov regularization in the dipolar frequency and distance domains and to approximate Pake transformation. Distance distribution with only narrow peaks are most reliably extracted by distance-domain Tikhonov regularization, while frequency-domain Tikhonov regularization is favorable for distributions with only broad peaks. For the quantification of distributions by their mean distance and variance, Hermite polynomial interpolation provides the best results. Distributions that contain both broad and narrow peaks are most difficult to analyze. In this case a high signal-to-noise ratio is strictly required and approximate Pake transformation should be applied. A procedure is given for renormalizing primary experimental data from protein preparations with slightly different degrees of spin labelling, so that they can be compared directly. Performance of all the data analysis procedures is demonstrated on experimental data for a shape-persistent biradical with a label-to-label distance of 5 nm, for a [2]catenane with a broad distance distribution, and for a doubly spin-labelled double mutant of plant light harvesting complex II     

Purification of a basic glycoprotein allergen from pollen of timothy by high-performance liquid chromatography

The use of high-performance ion-exchange and size-exclusion chromatography in the purification of the basic timothy pollen allergen antigen 30 (Ag 30) was investigated. The most efficient purification was achieved when an initial purification step on a CM-Sepharose CL-6B column was followed by chromatography on Mono S and TSK G 2000 SW columns. This procedure was highly reproducible and well suited for semi-preparative scale purification of the allergen. The purified allergen gave one band on isoelectric focusing, corresponding to a pI of 9.30. On fused rocket immunoelectrophoresis a single precipitate was obtained that coincided with the allergenic activity.     

具有耗散接头的三维欧拉─伯努利杆系的特征频率

本文计算了具有耗散接头的一般非共线的欧拉─伯努利或铁木辛柯杆系结构振动特征频率的传递矩阵．将允许结构是三维的，因此，一定要同时研究各种振动模式，包括纵向和扭转的振动。这种结构一般可以看作是由许多杆件首尾相接构成一条链条。允许有各种不同的减振器，甚至有些减振器是本结构内部形成的．我们也允许在结构中采用不同材料，杆件也可以是不同宽度。本文证明了可以利用渐近估计方法来求得近似的特征频率。     

Noncovalent linkage of telechelic oligo(dimethylsiloxanes) via end group attachment of host‐cyclodextrins and guest‐adamantanes or guest‐ferrocenes

In this article, we report the noncovalent linkage of terminal substituted oligo(dimethylsiloxanes) bearing cyclodextrins (CD) as host endgroups and adamantan or ferrocene, respectively, as guest endgroups. Structural characterization was performed by ¹H NMR‐, IR‐, and mass spectroscopy. Electron microscopy studies show significant differences in the surface structure of the individual derivatives. In addition, the ferrocene‐terminated di‐and poly(dimethylsiloxanes) are distinguished by a red‐ox activity and reversibility, which also makes the complexes between the ferrocene‐ and CD functionalized siloxanes switchable via electrochemical stimuli. The evidence for a successful complexation of the end groups, and thus the successful supramolecular formation of the siloxane strands, was even performed by shift of the protons in the ¹H NMR spectra. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2472–2482     

Synthese der L-glycero-D-manno-heptose

Chain extension of 2,3:5,6-di-O-isopropylidene-D-manno-furanose $\text{2}$ with 2-lithio-1,3-dithiane gives stereoselectively a derivative of D-glycero-D-galacto-heptose $\text{3}$. Conversion of the heptose $\text{2}$ by reduction of the aldehydo function and oxidation of the 7-OH group yields the D-glycero-D-manno-heptose $\text{18}$.     

Chirale synthese von (+)-lycoricidin

The synthesis of (+)-lycoricidine from D-glucose is described. Addition of the carbanion $\text{11}$ to the nitroolefine $\text{10}$ yields the adduct $\text{12}$ + $\text{13}$, from which crystalline lactone $\text{16}$ with $\text{muco}$-configuration in the cyclitol-ring can be isolated after hydrolysis and cyclization. Rearrangement to the lactam $\text{17}$ and elimination yields the (+)-lycoricidine.