Crossover from Hydrodynamics to the Kinetic Regime in Confined Nanoflows

We present an experimental study of a confined nanoflow, which is generated by a sphere oscillating in the proximity of a flat solid wall in a simple fluid. Varying the oscillation frequency, the confining length scale and the fluid mean free path over a broad range provides a detailed map of the flow. We use this experimental map to construct a scaling function, which describes the nanoflow in the entire parameter space, including both the hydrodynamic and the kinetic regimes. Our scaling function unifies previous theories based on the slip boundary condition and the effective viscosity

The morphology and clinical importance of the axillary arch

The axillary arch is the main variation of the axillary muscle. It was first described by Ramsay in 1795. In its classical form, it arises from the latissimus dorsi muscle and extends from this towards the pectoralis major, crossing the base of the axilla and creating a close relationship with the elements of the axillary neurovascular bundle. We describe the finding of 9 axillary arches, including one case of a bilateral arrangement. We develop a searching and finding technique for the axillary arch, essential for the safe and successful development of surgical procedures in the axillary region. Knowledge of this muscle variation and the possibility of finding it during axillary procedures is crucial for lymph node staging and lymphadenectomy and is also important for differential diagnosis in compressive pathologies of the axillary vessels and brachial plexus

Feasibility of computed tomography cholangiography using Gd-EOB-DTPA: a phantom study

Purpose: To assess the feasibility of computed tomography cholangiography (CTCG) using an hepatobiliary contrast agent for magnetic resonance imaging (Gd-EOB-DTPA). Material and Methods: We built three CT phantoms including a radiotransparent 2:1 scale representation of the extrahepatic and intrahepatic bile ducts up to the second order branches. By assuming standard contrast pharmacokinetics in an adult male patient of 70 kg, we filled phantoms with water and a volume of 4.05, 3.15 and 2.25 mL of 0.25 mmol/L concentrated Gd-EOB-DTPA, respectively. Volumes corresponded to the expected dose fraction (DF) of Gd-EOB-DTPA in the biliary tree given a i.v. dose to the patient (DP) of 9.0, 7.0 and 5.0 mL, respectively. Phantoms were scanned with a 64- row multidetector CT using a standardized protocol (120 kVp and 200-500 mA). We then performed a quantitative analysis by calculating the signal-tonoise ratio (SNR) of the biliary tree over the phantom background. Results: On visual analysis, the biliary tree phantoms appeared as hyperattenuating, regardless of contrast DF/DP. On quantitative analysis, the phantom with DF/DP = 3.15/7.0 mL, corresponding to the standard patient dose, showed average SNR (6.51) similar to that of the 2.25/5.0 mL phantom (SNR=6.45), although lower than the DF/DP = 4.05/9.0 mL phantom (SNR=11.56). Conclusion: In our model, a standard i.v. dose of Gd-EOB-DTPA determines acceptable hyperattenuation of the biliary tree on CT