Exact spin dynamics of inhomogeneous 1-d systems at high temperature

The evaluation of spin excitation dynamics in finite 1-d systems of spins with XY exchange interaction J acquired new interest because NMR experiments at high temperature (k_BTJ) confirmed the predicted spin wave behavior of mesoscopic echoes. In this work, we use the Jordan–Wigner transformation to obtain the exact dynamics of inhomogeneous chains and rings where the evolution is reduced to one-body dynamics. For higher dimensions, the spin excitations manifest many-body effects that can be interpreted as a simple dynamics of non-interacting fermions plus a decoherent process.     

Regioselective enzymatic glycosylation of natural polyhydroxylated compounds: galactosylation and glucosylation of protopanaxatriol ginsenosides.

Ginsenoside Rg1 (1), the most representative Ginsenoside from Panax Ginseng C.A. Meyer belonging to the protopanaxatriol family, has been galactosylated by action of the beta-(1,4)-galactosyltransferase (GalT) from bovine colostrum, using UDP-galactose as an activated sugar donor. The enzyme showed the well-known specificity for the formation of a beta-linkage with the C-4 OH of the glucose acceptor, but it was not able to discriminate between the two glucose moieties of 1, giving a mixture of mono- and digalactosylated derivatives. Other natural Rg1-analogues such as F1, Rh1, Re, as well as the synthetic derivative 6'-O-acetyl-Rg1 have been also galactosylated, giving monolactosyl derivatives. GalT was also able to accept UDP-glucose as an activated sugar donor, giving rise to cellobiosyl derivatives of Rg1.     

Some metrological aspects of ordinal measurements

Although some measurements can be made on any scale (including a continual scale), cost and speed considerations sometimes tip the scales toward using ordinal measurements. This paper presents a way to evaluate classical metrological characteristics, such as error, uncertainty and precision of single and repeated measurements based on the legitimate basic operations for ordinal data. The only legitimate measurement operations among ordinal variables are limited to equal or greater than/less than, the usual assessment measures such as average, standard deviation cannot be applied. Consequently, in order to receive reliable results and draw valid conclusions from ordinal measurements it is essential to develop and use only the appropriate methods.     

Synthesis and Crystal Structure of (Z)-4-(p-Bromo phenylthio)-3-(p-nitrobenzoyloxy)-3-buten-2-one

１　ＩＮＴＲＯＤＵＣＴＩＯＮＩｎｏｒｄｅｒｔｏｅｖａｌｕａｔｅｔｈｅｓｅｌｅｃｔｉｖｉｔｙａｎｄｒｅａｃｔｉｖｉｔｙｏｆｅｎｏｎｅｓａｓｄｉｅｎｏｎｅｐｈｉｌｅｓａｎｄｄｉｅｎｅｓｉｎＤｉｅｌｓＡｌｄｅｒｒｅａｃｔｉｏｎ,Ｐａｒａｌｔａｓｙｎｔｈｅｓｉｚｅｄβｆｕｎｃｔｉｏｎａｌｉｚｅｄｌａｃｅｔｙｌｖｉｎｙｌａｒｅｎｅｃａｒｂｏｘｙｌａｔｅｓａｓａｓｕｂｓｔｒａｔｅｏｆ１,３ｄｉｐｏｌａｒｃｙｃｌｏａｄｄｉｏｎｒｅａｃｔｉｏｎ〔１〕．Ｘｒａｙｃｒｙｓｔａｌｌｏｇｒａｐｈｉｃｓｔｕｄ…     

The effect of EGTA and Ca++ in regulation of the brain Na/K-ATP-ase by noradrenaline

Background  

The Na/K-ATPase activity of the brain synaptic plasma membranes (SPM) is regulated by noradrenaline (NA) and the synaptosomal factor SF (soluble protein obtained from the synaptosome cytosol). In the absence of SF, NA inhibits Na/K-ATPase, while, on addition of SF to the reaction medium, there is a NA-dependent activation of Na/K-ATPase . On the other hand, EGTA augments the Na/K-ATPase activity and attenuates the ability of NA to inhibit Na/K-ATPase.     

Single step oxidative binding of antibodies to hydrazide-modified eupergit C

A single step periodate oxidative binding of glycoproteins to synthetic polymeric matrices is proposed. By this procedure, the glycoprotein to be immobilized is simultaneously mixed with sodium periodate and a hydrazide-containing matrix. The carbohydrate moieties of the protein are oxidized and react with matrix. The single step reaction is faster than the commonly-used multistep procedure and it allows conjugation of minute amounts of glycoproteins to the matrix.     

13C-NMR of some ajmalane alkaloids

The ¹³C-NMR spectra of the alkaloid ajmaline ($\text{1}$) and its stereoisomers isoajmaline ($\text{2}$), sandwichine ($\text{3}$) and isosandwichine ($\text{4}$) are reported. The different stereochemistry at C (17), C(20) and C(21) of the four isomers can be directly ascertained by chemical shifts data.     

Intramolecular electron and energy transfer in an axial ZnP-pyridylfullerene complex as studied by X- and W-band time-resolved EPR spectroscopy

Light-driven electron transfer (ET) and energy transfer (EnT) in a self-assembled via axial coordination Zn-porphyrin-pyridylfullerene (ZnP-PyrF) complex were studied by time-resolved electron paramagnetic resonance (TREPR) spectroscopy at 9.5 GHz (X-band) and 95 GHz (W-band). The studies over a wide temperature range were carried out in media of different polarity, including isotropic toluene and tetrahydrofuran (THF), and anisotropic nematic liquid crystals (LCs), E-7 and ZLI-4389. At low temperatures (frozen matrices), photoexcitation of the ZnP donor results mainly in singlet-singlet EnT to the pyridine-appended fullerene acceptor. In fluid phases ET is the dominant process. Specifically, in isotropic solvents the generated radical pairs (RPs) are long-lived, with lifetimes exceeding that observed for covalently linked donor-acceptor systems. It is concluded that in liquid phases of both polar and nonpolar solvents the separation of the tightly bound complex into the more loosely bound structure slows down the back ET (BET) process. Photoexcitation of the donor in fluid phases of LCs does not result in the creation of the long-lived RPs, since the ordered LC matrix hinders the separation of the complex constituents. As a result, fast intramolecular BET takes place in the tightly bound complex. Contrarily to the behavior of covalently linked donor-acceptor systems in different LCs, the polarity of the LC matrix affects the ET process. Moreover, in contrast to covalently linked D-s-A systems, utilization of LCs for the coordinatively linked D-s-A complexes does not reduce the ET rates significantly.