80 research outputs found
Shrinkage of the distal renal artery 1 year after stent placement as evidenced with serial intravascular ultrasound
Shrinkage of the distal renal artery 1 year after stent placement as evidenced with serial intravascular ultrasound
High refractive index of melanin in shiny occipital feathers of a bird of paradise
Male Lawes's Parotia, a bird of paradise, use the highly directional reflection of the structurally colored, brilliant-silvery occipital feathers in their courtship display. As in other birds, the structural coloration is produced by ordered melanin pigmentation. The barbules of the Parotia's occipital feathers, with thickness ~3 µm, contain 6–7 layers of densely packed melanin rodlets (diameter ~0.25 µm, length ~2 µm). The effectively ~0.2 µm thick melanin layers separated by ~0.2 µm thick keratin layers create a multilayer interference reflector. Reflectance measurements yielded peak wavelengths in the near-infrared at ~1.3 µm, i.e., far outside the visible wavelength range. With the Jamin-Lebedeff interference microscopy method recently developed for pigmented media, we here determined the refractive index of the intact barbules. We thus derived the wavelength dependence of the refractive index of the barbules' melanin to be 1.7–1.8 in the visible wavelength range. Implementing the anatomical and refractive index data in an optical multilayer model, we calculated the barbules' reflectance, transmittance and absorptance spectra, thereby confirming measured spectra
Stent placement for renal arterial stenosis: where do we stand? A meta-analysis
PURPOSE: To perform a meta-analysis of renal arterial stent placement in
comparison with renal percutaneous transluminal angioplasty (PTA) in
patients with renal arterial stenosis. MATERIALS AND METHODS: Studies
dealing with renal arterial stent placement (14 articles; 678 patients)
and renal PTA (10 articles; 644 patients) published up to August 1998 were
selected. A random-effects model was used to pool the data. RESULTS: Renal
arterial stent placement proved highly successful, with an initial
adequate performance in 98% and major complications in 11%. The overall
cure rate for hypertension was 20%, whereas hypertension was improved in
49%. Renal function improved in 30% and stabilized in 38% of patients. The
restenosis rate at follow-up of 6-29 months was 17%. Stent placement had a
higher technical success rate and a lower restenosis rate than did renal
PTA (98% vs 77% and 17% vs 26%, respectively; P <.001). The complication
rate was not different between the two treatments. The cure rate for
hypertension was higher and the improvement rate for renal function was
lower after stent placement than after renal PTA (20% vs 10% and 30% vs
38%, respectively; P <.001). CONCLUSION: Renal arterial stent placement is
technically superior and clinically comparable to renal PTA alone
Shrinkage of the distal renal artery 1 year after stent placement as evidenced with serial intravascular ultrasound
The Educational and Professional Background of Central Bankers and its Effect on Inflation - An Empirical Analysis
- …