Biomedical subjects
Publications and source records attributed to F Vivaldi.
We develop a method to detect the presence of integrals of the motion in symplectic rational maps, by representing these maps over finite fields and examining their orbit structure. We find markedly different orbit statistics depending upon whether the map is integrable or not.
Intravenous administration of analgesic drugs is one of the most common ways to control post-operative pain. It can be used in almost all kinds of surgical interventions and particularly those of medium and high complexity. Besides, when other techniques are contraindicated because of clinical and/or managing problems, intravenous way finds its best application. Among analgesic drugs NSAID (ketorolac) and opioids (tramadol, morphine, buprenorphine) are most frequently used. As to administration techniques, elastomeric pump is, according to personal experience, a simple-to-manage, practical and precise device with lower cost respect to other administration set. Elastomeric pump is a single use reservoir that allows continuous administration of drugs with a uniform pre-set infusion speed. Finally, guide-lines, showing pre-load and infusion doses of analgesic drugs, based on pain intensity, are presented.
Multistable coupled map lattices typically support traveling fronts, separating two adjacent stable phases. We show how the existence of an invariant function describing the front profile allows a reduction of the infinitely dimensional dynamics to a one-dimensional circle homeomorphism, whose rotation number gives the propagation velocity. The mode locking of the velocity with respect to the system parameters then typically follows. We study the behavior of fronts near the boundary of parametric stability, and we explain how the mode locking tends to disappear as we approach the continuum limit of an infinite density of sites.
The case of a 63-year-old woman with a Bjork-Shiley mitral valve prosthesis who developed acute thrombosis of mitral prosthesis and acute pulmonary edema is described. Full clinical success was achieved with medical therapy with tissue-type plasminogen activator. The dosage of drug was titrated by serial echo-Doppler examinations of prosthetic structures and functional area. A low-dose (60 mg over 1 hour) of tissue-type plasminogen activator was sufficient to obtain thrombus resolution. Embolic or hemorrhagic complications were absent. This is the first report of successful use of Doppler echocardiography titrated low-dose of tissue-type plasminogen activator for acute thrombosis of mitral prosthetic valve.
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