Fourier transform infrared investigations of phosphate-silicate coatings on iron

The influence of silica addition and of the annealing on the structure and properties of phosphate coatings are investigated. It has been observed that silica stabilizes phosphates and reduces the transport of iron towards the surface.     

On factorization structures and epidense hulls

Characterizations of epidense subcategories of topological categories and of existence of epidense hulls have been described in [2, 3, 4]. In this paper a similar characterization is given in a much more general setting; for example the category need not have products. The relationship between finite factorization structures and existence of epidense hulls is investigated. It is found to be analogous to the relationship between general factorization structures and epireflective hulls.     

The crystal and molecular structure of chlorobis(N-ethyl-1 3-imidazolidine-2-thione)copper(I)

Summary The crystal structure of the title compound has been determined from x-ray diffractometer data by the heavy-atom method and refined anisotropically by least-squares calculations. Crystals are monoclinic, space groupP 2₁/c, with unit cell dimensions:a=7.321(1),b=14.622(2),c=14.827(2) Å,=92.95(2), Z=4. The finalR index is 4.6%. The copper coordination is trigonal, involving the sulphur atoms of twoN-ethyl-1,3-imidazolidine-2-thione molecules and one chlorine atom. The structure is held together by two intramolecular N-HCl hydrogen bonds and by normal van der Waals interactions.     

Osservazioni sulle caratteristiche dei grafi o singrammi

Riassunto Si introducono certi gruppi di numeri associati ad un grafo o singrammaG che vengono chiamati caratteristiche diG. Si studiano alcune proprietà delle caratteristiche e se ne fanno applicazioni a vari problemi sui grafi.

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Résumé On introduit certains groupes de nombres qui sont associés à un grapheG et qu’on appelle caractéristiques deG. Ou étudie quelques proprietés des caractéristiques et on en fait des applications a divers problèmes sur les graphes.

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Lavoro eseguito nell’ambito del Gruppo N. 26 del Comitato Naz. per la Mat. del C.N.R.     

Optimale Bestelltermine bei zufallsveränderlichen Lieferfristen

Zusammenfassung Ermittlung des günstigsten Bestellzeitpunktes, wenn die Zeitspanne zwischen der Bestellung und der Lieferung eine Zufallsveränderliche mit bekannter Verteilung ist.

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Summary Determination of the optimal time for placing orders in those cases where the time interval between order and supply is a random variable with known distribution.

     

N,N′-dialkylsubstituted Imidazolidine-2-thionecopper(I) complexes. X-ray analysis of chloro-bis(N,N′-dimethylimidazolidine-2-thione)copper(I)

Summary New complexes of copper(I) withN,N-dialkylsubstituted imidazolidine-2-thione ligands were prepared by reduction of CuX₂ (X = Cl or Br). The i.r. spectra show that in all the complexes the ligand coordinates through the sulphur atom. The crystal structure of chloro-bis(N,N-dimethylimidazolidine-2-thione)copper(I) has been determined from x-ray diffraction data. Crystals are monoclinic. space groupC ₂, with unit cell dimensions:a = 16.022(15),b = 9.942(10),c = 15.112(15) A, = 139.84(10)², Z = 4. The final R index is 5.2%. The copper coordination is trigonal, involving sulphur atoms of the two ligands and One chlorine atom. The steric effect of the two methyls imposes a rotation of the imidazolidine rings with respect to the coordination plane. The dihedral angle between the mean plane of thiourea moieties. parallel one with the other. and the coordination plane is 119.3°.This work was supported by the National Research Council (C.N.R.) of Rome.     

A new tricyclic triketone from tandem condensation reactions

Perhydrophenanthrene-1,5,10-trione (6) was isolated from the reaction of methyl 3-(carboxymethyl)cyclohexanone and cyclohexenone in a tandem Michael-Claisen reaction. NMR and X-ray analysis confirmed the structure of the product.     

Atomic force microscopy study of early morphological changes during apoptosis

Apoptosis is defined by a distinct set of morphological changes observed during cell death including loss of focal adhesions, the formation of cell membrane buds or blebs, and a decrease in total cell volume. Recent studies suggest that these dramatic morphological changes, particularly apoptotic volume decrease (AVD), are an early prerequisite to apoptosis and precede key biochemical time-points. Here we use atomic force microscopy to observe early stage AVD of KB cells undergoing staurosporine-induced apoptosis. After a 3-h exposure to 1 microM staurosporine, a 32% decrease in total cell height and a 50% loss of total cell volume is observed accompanied by only a 15% change in cell diameter. The observed AVD precedes key biochemical hallmarks of apoptosis such as loss of mitochondrial membrane potential, phosphatidyl serine translocation, nuclear fragmentation, and measurable caspase-3 activity. This suggests that morphological volume changes occur very early in the induction of apoptosis.     

Metabolic profile of lettuce leaves by high-field NMR spectra

A detailed analysis of the proton high-field NMR spectra of aqueous and organic extracts of lettuce leaves is reported for the first time. A combination of COSY, TOCSY, (1)H-(13)C HSQC, (1)H-(13)C HMBC bidimensional sequences and DOSY was used to assign each spin system and to separate the components of the complex patterns. A large number of water-soluble metabolites belonging to different classes such as carbohydrates, polyols, organic acids and amino acids were fully assigned. Moreover, the complex spectra of metabolites extracted in organic solvents belonging to sterols, fatty acids, diacylglycerophospholipids, galactosyldiacylglycerols, sulpholipids, pheophytins, carotenoids and hydrocarbons were also assigned.