Intermittent contact hydration scanning probe microscopy.

Hydration scanning probe microscopy is a technique similar to scanning tunneling microscopy, in which the probe current, sustained by the slight surface conduction of a thin hydration layer covering an insulating support surface, is essentially electrochemical in nature instead of electronic tunneling. Such a technique allows the imaging of a great variety of samples, including insulators, provided that they are hydrophilic, as well as the study of molecular samples of biological interest (such as DNA) fixed on a suitable supporting surface. The main problem to obtain stable and reproducible images comes from the very critical determination of the operating conditions under which the probe-hydration layer interaction does not lead to the formation of a relatively large water meniscus. It has been suggested that this issue can be removed by adding a high frequency oscillation to the probe movement, as in tapping atomic force microscopy. Meniscus formation and breakup have been investigated in order to determine the best values for the amplitude and the frequency of the oscillation. Results obtained in this mode are discussed in comparison with the usual continuous contact mode.

Implementation on a desktop computer of the real time feedback control loop of a scanning probe microscope.

A software package has been developed to implement the real time feedback control loop needed in scanning probe microscopy on a general purpose desktop computer of the current high-speed/multicore generation. The main features of the implementation of both the feedback loop and the control of the experiment on the same computer are discussed. The package can work with several general purpose data acquisition boards and can be extended in a modular way to further board models; timing performance has been tested with several hardware configurations and some applications common in scanning probe microscopy. The package is available under an Open Source license.

A study of the ionic conduction of mica surface by admittance spectroscopy.

The ionic conduction on the surface of humid mica has been analyzed by admittance spectroscopy as a function of relative humidity for different surface treatments. Measurements at low frequency indicate that water adsorption proceeds first in the form of a strongly adsorbed uniform thin layer, then with the formation of highly inhomogeneous thick aggregates.

Haemostasis during transvesical prostatic adenomectomy. A controlled trial on the effect of drugs with antifibrinolytic and thrombin-like activities.

Blood loss, plasma fibrinolytic activity, prothrombin, P.T.T., and fibrinogen plasma levels were measured in 30 patients subjected to transvesical adenomectomy. These parameters were evaluated during 7 consecutive days after the operation. Ten patients received the antifibrinolytic substance (AMCHA), ten patients received Bothrops Jararaca venom extract, and ten patients served as controls. The results show that the coagulating fraction of Bothrops Jararaca snake venom reduces intraoperative bleeding without influencing the haemostatic balance. Postoperative haematuria could be reduced by antifibrinolytic agents.

[The in-vivo effect of dihydroergocristine on human platelet function]. / Effetto "in vivo" della diidroergocristina sulla funzione di piastrine umane.

An acute test was run on healthy volunteers to assess the effect of i.v. dihydroergocristine methansulphonate on platelet function. The number of platelets was virtually unaffected, whereas adhesion to glass was significantly reduced. A direct and specific effect was noted on the 1st, adrenaline aggregation wave, while the 2nd wave (expression of ADP) induced aggregation did not appear to have been significantly altered. It is felt that further examination of the alpha-adrenergic block induced by the drug should be under-taken in view of the recent literature data which explain the inability of commonly employed anti-aggreganting drugs, such as acetylsalicylic acid, to prevent and treat atherothrombosis, in spite of the encouraging experimental results.