Dimensional analysis, a standard method of Fluid Mechanics, was applied to the field of venous hemodynamics. Three independent physical quantities, velocity, length and pressure, were chosen and seven other ones were used to derive the non-dimensional terms. The mathematical burden was reduced to the minimum and the attention was focused on the results. Among them, a new formulation of an already known non-dimensional term, recalled the flow-length (FL), was identified and selected for a deeper experimental study.

Phase 2 can be monitored, following the viral load dosing curves in urban waste water, as the SARS-COV2 virus can be traced into the fecal material. This low-cost method can be moved upstream for a strict control of smaller areas. The city of Naples has a capillary network of sewers, which allow a much finer tracing. The method could be expanded to all the territory of Italy and also to other countries.

A phantom is a physical object to simplify device testing and clinical training. An industrial device is more reliable for device testing in quality control procedures, though it is expensive. When precision requirements are not so strict as it occurs in training, people prefer to use home-made phantoms, though many of these artisanal methods use animal products. The current paper illustrates a few alternative vegetal phantoms. Agar is a widely used material in laboratory investigations and can be used to contain ultrasound targets. Another quick and effective alternative is given by tofu. Target sizes and flow ultrasound measurements can be easily effected using a phantom and training can be planned and repeated as much as required. The current paper shows how low-cost animal phantoms can be perfectly replaced by low-cost vegetal ones for clinical and training purposes. Vegetal phantoms can be classified as possible realizations of the Replace, the 1st of the 3Rs pre-requisites for non-animal experiments.

Figure 1-Collateral circulation bypassing an obstruction in an arterial and venous schematic example. Half arrows point to the direction of flow, red for arteries, blue for veins. Yellow for inverted flow. Black for occlusion. A, inverted main trunk. B, inverted collateral path. E, excluded region.

Maybe just a few people know that on May 20 th , 2019 a global revolutionary change of the units of measure will involve all human activities everywhere in the world. No panic, please ! Nothing at all will really change in our daily life.