Nanoscale dielectric microscopy of non-planar samples by lift-mode electrostatic force microscopy.

Lift-mode electrostatic force microscopy (EFM) is one of the most convenient imaging modes to study the local dielectric properties of non-planar samples. Here we present the quantitative analysis of this imaging mode. We introduce a method to quantify and subtract the topographic crosstalk from the lift-mode EFM images, and a 3D numerical approach that allows for extracting the local dielectric constant with nanoscale spatial resolution free from topographic artifacts. We demonstrate this procedure by measuring the dielectric properties of micropatterned SiO2 pillars and of single bacteria cells, thus illustrating the wide applicability of our approach from materials science to biology.

The central venous catheter in a bone marrow transplant unit: an unresolved problem.

Bone marrow transplantation (BMT) is feasible with a bearable risk and discomfort for patients only if good venous access is provided. Therefore a major task for nurses of a BMT unit is management of a patient's central venous catheter. There is not general agreement about the procedure of handling a CVC and infection prophylaxis. We collected data from some Italian BMT and hematology units by means of a questionnaire. The responses to this questionnaire were not comparable except for some particulars. Each center has its own ritual procedure; even the use of sterile gloves while handling the most dangerous connections of the catheter is not the rule everywhere. It is noteworthy that only a minority of physicians are able to handle a catheter correctly.