Calibration of a polychromatic CT equipment for biological tissue samples enriched with magnetic nanoparticles.

Micro-computed tomography (µCT) is a widely used imaging technique. Tomography has been used to study the distribution of magnetic nanoparticles within cancerous tissue after minimal-invasive cancer treatments such as magnetic drug targeting and magnetic hyperthermia. But not only the distribution is a relevant factor for the sucess of these therapeutic aproaches. The concentration of the magnetic nanoparticles within the respective tissue is also of great impact. In this paper we present a calibration procedure of a µCT-equipment for biological tissue samples enriched with magnetic nanoparticles developed to enable a semi-quantitative evaluation of 3-dimensional data sets. (© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

NMR and theoretical calculations: a unified view of the cis/trans isomerization of 2-substituted thiazolidines containing peptides

The cis/trans isomerization of peptides containing the pseudoproline (4R)-thiazolidine-4-carboxylic acid Cys(Psi (R1,R2) pro) is investigated from both an experimental and a theoretical point of view by NMR and DFT calculations. A series of Ac-Cys(Psi(R1,R2) pro)-OCH3 and Ac-Cys(Psi(R1,R2) pro)-NHCH3 peptides were prepared to assess the influence of the substitution at the C2 position as well as of the amide following the thiazolidine residue. For each compound, the cis/trans ratio along with free energy, the puckering of the thiazolidine ring and the free rotational energy barrier are reported and discussed. We observe there is a pronounced effect of the C2 substituents and of the chirality upon the cis/trans ratio with the population of the cis content in the order (2R)-Cys(Psi(CH3,H) pro)<(2S)-Cys(Psi(H,CH3) pro)相似文献   

Geometry of Critical Loci

Let :(Z,z)(U,0) be the germ of a finite (that is, proper with finite fibres)complex analytic morphism from a complex analytic normal surfaceonto an open neighbourhood U of the origin 0 in the complexplane C². Let u and v be coordinates of C² defined on U. Weshall call the triple (, u, v) the initial data. Let stand for the discriminant locus of the germ , that is,the image by of the critical locus of . Let ()_A be the branches of the discriminant locus at O whichare not the coordinate axes. For each A, we define a rational number d by where I(–, –) denotes the intersection number at0 of complex analytic curves in C². The set of rational numbersd, for A, is a finite subset D of the set of rational numbersQ. We shall call D the set of discriminantal ratios of the initialdata (, u, v). The interesting situation is when one of thetwo coordinates (u, v) is tangent to some branch of , otherwiseD = {1}. The definition of D depends not only on the choiceof the two coordinates, but also on their ordering. In this paper we prove that the set D is a topological invariantof the initial data (, u, v) (in a sense that we shall definebelow) and we give several ways to compute it. These resultsare first steps in the understanding of the geometry of thediscriminant locus. We shall also see the relation with thegeometry of the critical locus.     

Sequences of reflection functors and the preprojective component of a valued quiver

This paper concerns preprojective representations of a finite connected valued quiver without oriented cycles. For each such representation, an explicit formula in terms of the geometry of the quiver gives a unique, up to a certain equivalence, shortest (+)-admissible sequence such that the corresponding composition of reflection functors annihilates the representation. The set of equivalence classes of the above sequences is a partially ordered set that contains a great deal of information about the preprojective component of the Auslander-Reiten quiver. The results apply to the study of reduced words in the Weyl group associated with an indecomposable symmetrizable generalized Cartan matrix.     

Über die Einwirkung von Phosphorpentachlorid auf o-Chinolacetate

Zusammenfassung Die Einwirkung von Phosphorpentachlorid auf o-Chinolacetate führt zur Bildung von Reaktionsprodukten, aus denen durch Hydrolyse m-chlorsubstituierte Phenylphosphorsäuren hervorgehen. Diese liefern bei thermischer Spaltung oder bei alkalischer Hydrolyse entsprechende m-Chlorphenole.     

The graphs with only self-dual signings

Given a graph G, it is possible to attach positive and negative signs to its lines only, to its points only, or to both. The resulting structures are called respectively signed graphs, marked graphs and nets. The dual of each such structure is obtained by changing every sign in it. We determine all graphs G for which every suitable marked graph on G is self-dual (the M-dual graphs), and also the corresponding graphs G for signed graphs (S-dual) and for nets (N-dual.A graph G is M-dual if and only if G or ? is one of the graphs K_2m, 2K_m, mK₂, K_m + K₂ or 2C₄. The S-dual graphs are C₆, 2C₃, 2C₄, 2K_1n, 2nK₂, K_1,2n, nK_1,2, K_2n, K?_n and all graphs obtained from these by the addition of isolated points. Finally, the only N-dual graph other than -K_2n is 2K₂.