Three-dimensional graphing representing six variables for speed and separation performance in liquid chromatography.

The two variables, flow rate and column length, enable naive determination of the number of theoretical plates (N) in isocratic elution; this, in turn, enables the formation of a three-dimensional graph with N as the z-axis. An alternate three-dimensional graph with N as the z-axis can be drawn, then, with the alternate basal plane illustrating the pressure drop and hold-up time. In this article, the pressure drop and hold-up time are formulated so as to be represented unitarily in the former graph, because the flow rate and column length interact simultaneously as operational variables.

Three approaches to improving performance of liquid chromatography using contour maps with pressure, time, and number of theoretical plates.

Attempts to improve HPLC performance often focus on increasing the speed or separation performance. In this article, both the flow rate and column length are optimized as separation conditions, while observing the number of theoretical plates and hold-up time with isocratic elutions. In addition, the upper pressure limit must be simultaneously considered as the boundary condition.

Is surgical parent artery occlusion effective for intracranial aneurysms measuring over 10 mm in size? Result from long-term follow-up of size changes and outcomes.

Background: There have been no long-term follow-up reports pertaining to chronological size changes in large or giant unruptured intracranial aneurysms treated with surgical parent artery occlusion (PAO). The object of this study is to investigate the utility and safety of surgical PAO by conducting a long-term follow-up of chronological aneurysm size changes and outcomes.

Methods: A retrospective study of 21 unruptured intracranial aneurysms measuring over 10 mm (20 patients) treated with surgical PAO in the period 2012-2017 was conducted.

Three-dimensional Representation Method Using Pressure, Time, and Number of Theoretical Plates to Analyze Separation Conditions in HPLC Columns.

There has been considerable discussion of the speed performance of HPLC separation, especially regarding the relationship between theoretical plates and hold-up time. The fundamental discussion focuses on the optimal velocity, u, which gives a minimal height equivalent to a theoretical plate of the van Deemter plot. On the other hand, Desmet's method, using the kinetic performance limit (KPL), calculates the highest performance with a constant pressure drop, without focusing solely on the optimal velocity.

Optic neuropathy produced by a compressed mucocele in an Onodi cell.

Purpose: To describe a patient with compressive optic neuropathy caused by a mucocele in an Onodi cell.

Design: Interventional case report.

Methods: A 73-year-old man complained of sudden visual loss in the left eye 10 days after cataract surgery.