Hyperfine interactions of111Cd in ion-implanted face centered cubic cobalt

The magnetic-dipole and electric-quadrupole hyperfine interactions of¹¹¹Cd probes in fcc cobalt after implantation of radioactive¹¹¹In⁺ ions have been investigated by PAC measurements with fast BaF₂ detectors. Six different sites of the probe atoms could be distinguished and characterized by their hyperfine parameters and annealing behaviour. Besides the substitutional site, three sites are assigned to In-vacancy complexes which are formed athermally in the implantation process or by thermally-activated trapping of lattice defects in annealing stage III. The remaining two sites are attributed to In located in stacking faults or hcp regions of the host. Systematic trends of impurity hyperfine fields in defect sites become evident from a comparison with other impurity-host combinations. The temperature dependence of the magnetic hyperfine fields has been measured between 20 K and 390 K. Large differences found for the various sites are discussed.     

Lithiumaluminiumhydrid als Reagens zur mikroanalytischen Bestimmung funktioneller Gruppen

Zusammenfassung Es wird gezeigt, daß die vonA. Soltys angegebene Apparatur zur Bestimmung des aktiven Wasserstoffes nachZerewitinoff sehr geeignet ist, den bei der Reaktion vonLithiumaluminiumhydrid mit organischen Substanzen entwickelten Wasserstoff bei einer Einwaage von 3 bis 5 mg quantitativ zu bestimmen. Bisher wurden hauptsächlich aromatische Verbindungen aus der Reihe der Carbonsäure, Phenole, Nitrokörper und Amine untersucht. Dabei ergab sich, daß die quantitative Verfolgung der Reaktion für die Konstitutionsaufklärung von Bedeutung ist. Einige an dieser Stelle mitgeteilte Resultate bei aromatischen Carbonsäuren und Phenolen zeigen die Zuverlässigkeit der Methodik zur Bestimmung des reaktionsfähigen Wasserstoffes.

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Summary It was shown that the apparatus devised bySoltys for the determination of active hydrogen according toZerewitinoff is well suited to the quantitative measurement of the hydrogen evolved by the reaction of lithium-aluminium hydride with organic materials, when a sample of 3–5 mg is taken. Up to the present, the studies have been limited chiefly to aromatic compounds: carboxylic acids, phenols, nitrocompounds and amines. It was found that the quantitative following of the reaction is important when the objective is to clarify questions regarding chemical constitutions. Several of the results reported here on aromatic carboxylic acids and phenols demonstrate the reliability of the method for the determination of reactive hydrogen.

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Résumé On montre que l'appareil donné parSoltys pour doser l'hydrogène actif suivant la méthode deZerewitinoff est tout à fait approprié pour déterminer quantitativement, sur une prise de 3 à 5 mg, l'hydrogène dégagé des substances organiques au cours de la réaction de l'hydrure d'aluminium-lithium. On a déjà expérimenté principalement des composés aromatiques de la série des acides carboxyliques, des phénols, des dérivés nitrés et des amines. Il en résulte, en outre, que l'évolution quantitative de la réaction est intéressante pour établir la constitution. Quelques-uns des résultats communiqués ici pour les acides carboxyliques aromatiques et les phénols montrent la fidélité de la méthode pour le dosage de l'hydrogène mobile.

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(Unter Mitarbeit von E. Schiviz-Schivizhoffen.)

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Mit 2 Abbildungen.     

Die mikroanalytische Bestimmung der Carbonylgruppe

Zusammenfassung An Hand einer Vergleichstabelle wird die Überlegenheit der mikroanalytischen Bestimmung von Carbonylgruppen in organischen Verbindungen mit 2,4-Dinitrophenylhydrazin nach Schöniger-Lieb gegenüber der gasvolumetrischen Mikromethode von Strache-Falkenhausen gezeigt. Während diese Autoren Phenylhydrazinchlorhydrat als Reagens verwenden und den Stickstoff gasvolumetrisch erfassen, wird nach unserer Methode das überschüssige Reagens maßanalytisch ermittelt. Zu diesem Zwecke wird das Dinitrophenylhydrazin mit Titan(III)-chlorid reduziert und das nicht oxydierte Titan(III)-chlorid mit Eisen(III)ammoniumsulfatlösung bestimmt.     

EPR on bis(1,2-dithiosquarato)cuprate(II) in the bis(1,2-dithiosquarato)nickelate(II) host lattice — structure and spectroscopy‡

EPR spectroscopy is a well suited analytical tool to monitor the electronic situation around paramagnetic metal centres as copper(II) and therefore the structural influences on the paramagnetic ion. 1,2-Dithiosquaratometalates are available by direct synthesis from metal salts with dipotassium-1,2-dithiosquarate and the appropriate counter cations. Synthesis and characterisation of bis(benzyltributylammonium)1,2-dithiosquaratonickelate(II), (BzlBu₃N)₂[Ni(dtsq)₂], and bis(benzyltributylammonium)1,2-dithiosquaratocuprate(II), (BzlBu₃N)₂[Cu(dtsq)₂], with benzyltributylammonium as the counter ion is reported and the X-ray structures of two complexes, (BzlBu₃N)₂[Ni(dtsq)₂] and (BzlBu₃N)₂[Cu(dtsq)₂], are presented. Both complexes, crystallising in the monoclinic space group P2₁/c, are isostructural with only small differences in the coordination sphere due to the different metal ions. The diamagnetic nickel complex is therefore well suited as a host lattice for the paramagnetic Cu(II) complex to measure EPR for additional structural information.     

Multifunctional thin films of lactoferrin for biochemical use deposited by MAPLE technique

Lactoferrin (Lf) is an iron-binding glycoprotein present in almost all mammalian secretions which plays an important role in host defense against microbial and viral infections. The protein has been reported to also have anti-inflammatory activity and antitumoral effects in vitro and in vivo.Thin films of Lf were deposited on silicon, quartz and Thermanox plastic coverslip substrates by Matrix Assisted Pulsed Laser Evaporation (MAPLE) technique, using a Nd:YAG laser working at 266 nm, at different laser fluences (0.1-0.8 J cm⁻²). The deposited layers have been characterized by Fourier Transformed Infra-Red spectroscopy (FTIR), and the morphology of the various substrates was investigated by Atomic Force Microscopy (AFM). The biocompatibility of lactoferrin thin films was evaluated for each substrate, by in vitro biochemical tests.     

Approximating fractional derivatives in the perspective of system control

The theory of fractional calculus goes back to the beginning of the theory of differential calculus, but its application received attention only recently. In the area of automatic control some work was developed, but the proposed algorithms are still in a research stage. This paper discusses a novel method, with two degrees of freedom, for the design of fractional discrete-time derivatives. The performance of several approximations of fractional derivatives is investigated in the perspective of nonlinear system control.