Calculation of diamagnetic susceptibilities from the Thomas–Fermi–Amaldi theory for ions

The importance of the Fermi–Amaldi correction for the Thomas–Fermi theory for ions is analyzed. An analytical trial electron density with a proper limiting behavior has been chosen and the Thomas–Fermi–Amaldi energy expression is minimized in a variational way for several closed-shell ions. The obtained optimum electron densities have been used for calculating the diamagnetic susceptibilities, and a comparison with other theoretical results and available experimental data is performed.     

Unicité de la solution de l'équation monodimensionnelle ou à symétrie sphérique d'un gaz visqueux et calorifère

In questo articolo dimostriamo l'unicità della soluzione (globale in tempo) dell'equazione monodimensionale o a simmetria sferica di un gas viscoso e termoconduttore con la superficie libera. In questo risultato il limite inferiore della densità ρ può essere uguale a 0. Assieme al teorema di esistenza dimostrato nei lavori precedenti, costituisce il teorema di esistenza e di unicità (globale in tempo) per questa equazione.     

Determination of intrinsic properties of immobilized enzymes

Staphylococcal nuclease has been insolubilized, directly through its amino groups, on CNBr-activated Sepharose 2B. For kinetic studies, a small substrate (thymidine 5′-(p-nitrophenyl phosphate) 3′-phosphate) has been used to measure the hydrolytic activity. With this system the absence of diffusional limitation has been proven. Eadie-Hofstee analysis of the data has been employed to determine the intrinsic kinetic constants of the insolubilized enzyme. Thek _cat-pH andK _M−pH profiles and the activation energies are similar for the soluble and for the insolubilized nuclease. At the same time conditions are established in which a stirred batch reactor containing particles of insolubilized nuclease behaves as an open system.     

10-Gbit/s Serial Optical Interconnection for an ATM Switch

Serial optical interconnection is proposed for connections in a Torus asynchronous transfer mode switch. A cross-point switch was developed that operates at a bit rate of 20 Gbit/s. The switching operation was successfully performed using cascaded cross-point switches through an optical interconnection configuration consisting of commercial optoelectronics devices. The measured switching rate was 10 Gbit/s, and it was limited by the responses of the optoelectronics devices.     

Mössbauer spectroscopy of metals from birth to death

In today's metallurgy, precision techniques, such as X-ray and electron diffraction, electron microscopy, infrared spectroscopy and electron probe micro-analyzer, are being indispensably used, and, comparing to them, Mössbauer spectroscopy is not inferior at all in usefulness, convenience and cost benefit. Actually, however, it is not yet popular among the metallurgists probably because people believe that the Mössbauer effect is a difficult physics, radioactive sources are difficult to handle, and spectral analyses are complicated. These beliefs are in fact groundless and must be dissolved for further diffusion of this useful Mössbauer technique in metals and other industries. The present introductory talk intends to help people's better understanding and no anxiety for using the Mössbauer spectroscopy by showing how it can be applied to various problems of metals and alloys from their birth to the end, that is, from the study of minerals and ores before smelting to that of corrosion and other failures. Firstly, the principle of Mössbauer spectroscopy will be explained with simplest illustrations together with simple pictures of apparatuses including the high temperature furnace and the high pressure cell. In the second will be shown typical examples of Mössbauer patterns of magnetite, carbon steel and other alloys, with indications of how to analyze the seemingly complicated spectra. Some other examples will be shown with special apparatuses easy to measure. The usefulness and convenience of Mössbauer spectroscopy will be understood again from these examples. More examples will be on amorphous alloys and other advanced materials.     

Study of the nitric oxide system in the rat cerebellum during aging

Background  

The cerebellum is the neural structure with the highest levels of nitric oxide, a neurotransmitter that has been proposed to play a key role in the brain aging, although knowledge concerning its contribution to cerebellar senescence is still unclear, due mainly to absence of integrative studies that jointly evaluate the main factors involved in its cell production and function. Consequently, in the present study, we investigate the expression, location, and activity of nitric oxide synthase isoenzymes; the protein nitration; and the production of nitric oxide in the cerebellum of adult and old rats.     

Control of molecular interactions by the hollow of coordination cages

Coordination self-assembly entities have been demonstrated to be useful and powerful alternatives for the construction of predefined and well-organized architectures. Self-assembled coordination cages, which possess an inner hydrophobic cavity, can be utilized to move substrates closer by encapsulation so enabling their interaction with each other and exhibiting of non-classical physical properties.