Complex compounds with rhodium(III) of enantiomers of nicotine

The synthesis, characterization and comparison of the enantiomeric transition metal complexes, trans-[Rh-(S-(–)-nicH⁺)₄Cl₂](PF₆)₅ and trans-[Rh-(R-(+)-nicH⁺)₄Cl₂](PF₆)₅, and of the racemic mixture trans-[Rh-(RS-(±)-nicH⁺)₄Cl₂](PF₆)₅ are described.     

Croissance du nombre de classes dans desZ l -extensions liées aux corps quadratiques imaginaires

Sans résumé     

Isomers of α-amino acids with copper(II). Part VI. Novel equilibria at high pH in copper(II):Amino-acid solutions

Summary Circular dichroism spectra show the presence at high pH of a new pH-dependent equilibrium for aqueous solutions of amino-acid with copper(II) ions. Measurements are interpreted in terms of an apparent acid dissociation constant. A typical value for pK_a is 12.17 for alanine. Electron spin resonance and circular dichroism suggest that the high pH form is a monomeric hydroxobisalaninato-complex of copper(II).Part V. see Ref. 1.     

Novel methodology for 3D reconstruction of carotid arteries and plaque characterization based upon magnetic resonance imaging carotid angiography data

In this study, we present a novel methodology that allows reliable segmentation of the magnetic resonance images (MRIs) for accurate fully automated three-dimensional (3D) reconstruction of the carotid arteries and semiautomated characterization of plaque type. Our approach uses active contours to detect the luminal borders in the time-of-flight images and the outer vessel wall borders in the T(1)-weighted images. The methodology incorporates the connecting components theory for the automated identification of the bifurcation region and a knowledge-based algorithm for the accurate characterization of the plaque components. The proposed segmentation method was validated in randomly selected MRI frames analyzed offline by two expert observers. The interobserver variability of the method for the lumen and outer vessel wall was -1.60%±6.70% and 0.56%±6.28%, respectively, while the Williams Index for all metrics was close to unity. The methodology implemented to identify the composition of the plaque was also validated in 591 images acquired from 24 patients. The obtained Cohen's k was 0.68 (0.60-0.76) for lipid plaques, while the time needed to process an MRI sequence for 3D reconstruction was only 30 s. The obtained results indicate that the proposed methodology allows reliable and automated detection of the luminal and vessel wall borders and fast and accurate characterization of plaque type in carotid MRI sequences. These features render the currently presented methodology a useful tool in the clinical and research arena.     

Synthesis and characterisation of some salts of the ions [Rh(Oxalato)2(Rpy)2]−

Salts of three bisoxalato bis(pyridine) species, trans-[Rh(ox)₂(py)₂]^?, trans-[Rh(ox)₂(3-Mepy)₂]^? and trans-[Rh(ox)₂(4-Mepy)₂]^? have been isolated from the substitution of N-heterocycles into trisoxalatorhodate(III) and characterised on the basis of ¹H NMR and ¹³C NMR spectra, which are similar to that of the trans-[Co(oxalato)₂ (R-py)₂]^? complex.     

Adducts of coordination compounds—12: New hydrogen dinitrates and their structures

The new compounds trans-[Ru(pyr)₄Cl₂[H(ONO₂)₂] and [C₁₃H₉NH][H(ONO₂)₂] have been characterised (where pyr is pyridi     

tert-Butylmethoxyphenylsilyl ether - a new selective,stable alcohol protecting group with remarkable lability to fluoride.

$\text{tert}$-Butylmethoxyphenylsilyl ethers, which can be formed from primary, secondary or tertiary alcohols and $\text{tert}$-butylmethoxyphenylsilyl bromide, are selectively cleaved by fluoride in the presence of other silyl ethers.