What is the Z-effect?
The Z-effect phenomenon is a potential complication of two lag screw intramedullary nail designs used for fixation of intertrochanteric hip fractures, in which the inferior lag screw migrates laterally and the superior lag screw migrates medially during physiologic loading.
What is tip apex distance?
This measurement, the tip-apex distance, is the sum of the distance from the tip of the lag screw to the apex of the femoral head on an anteroposterior radiograph and this distance on a lateral radiograph, after controlling for magnification.
What is Slater rule in chemistry?
The general principle behind Slater’s Rule is that the actual charge felt by an electron is equal to what you’d expect the charge to be from a certain number of protons, but minus a certain amount of charge from other electrons.
How is tad calculated?
By calculating the sum of the distance from the tip of the screw to the apex of the femoral head on anteroposterior and lateral views the TAD is found.
When implanting a DHS or TFNA the physician wants a tip apex distance of?
The tip apex distance (TAD) should be less than 25 mm to prevent DHS cut-out or failure, which most often happens if the screw is placed too anterior or too superior.
What is the Zeff of oxygen?
The effective nuclear charge for the outermost electron of an oxygen atom is. A: 4.55. B: 5.35.
What does Z effective mean?
effective nuclear charge
The effective nuclear charge (often symbolized as Zeff or Z*) is the net positive charge experienced by an electron in a multi-electron atom. The term “effective” is used because the shielding effect of negatively charged electrons prevents higher orbital electrons from experiencing the full nuclear charge.
Which is a complication of the Z Effect?
Is there a way to reproduce the Z Effect?
The current investigation was undertaken in an attempt to reproduce the Z-effect phenomenon in a laboratory setting. Sixteen different simulated femoral head and neck constructs having varying compressive strengths were created using four densities of solid polyurethane foam and instrumented with a two-screw cephalomedullary intramedullary nail.
Is the chemical PFNA detectable in the environment?
Perfluorononanoic acid (PFNA) is a fluorinated organic chemical found at low levels in the environment, but is detectable in humans and wildlife. The present study compared the pharmacokinetic properties of PFNA in two laboratory rodent species.
Is there a Z-effect after a long nail?
The incidence of (reversed) Z-effect in this study was 9% ( n = 80); 6 out of 7 Z-effects occurred in the short nail group, which was not significant. Patients who were treated with a long nail had a significant larger number of complications in comparison with the short nail group (median 2 vs 0.5, p = 0.001).