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1.
Ultrasound Med Biol ; 20(8): 699-703, 1994.
Artículo en Inglés | MEDLINE | ID: mdl-7863559

RESUMEN

Systematic differences have been found in measurements of femur lengths made with (1) a Hitachi EUB 25, representative of older machines in use when most of the femur length-gestation curves were produced; and (2) a modern high resolution machine (Acuson 128). It is proposed that these differences may be accounted for by the different beam widths of the two systems. Six operators measured the femur lengths of several normal fetuses using both machines. Analysis of the results revealed a highly significant (p < 0.005) difference between machines, that did not correlate with femur length (r = -0.022). The mean difference was 1.02 +/- 0.33 mm (Hitachi larger). The mean femur length was 46.44 mm (n = 57). Pulse-echo beam plots showed that, for the probes used, the Hitachi 6 dB beam width is greater than the Acuson beam width by typically 2 mm, depending on the range and Acuson focus setting. This beam width difference can account for the difference in femur length measurements, if allowance is made for the variable angle between femurs and ultrasound beams. The results suggest that femur length-gestation curves for use with modern machines should be based on measurements made with modern machines.


Asunto(s)
Fémur/diagnóstico por imagen , Ultrasonografía Prenatal/instrumentación , Análisis de Varianza , Femenino , Fémur/embriología , Humanos , Técnicas In Vitro , Embarazo , Ultrasonografía Prenatal/métodos
2.
Ann R Coll Surg Engl ; 64(2): 108-10, 1982 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-7065596

RESUMEN

The little-known technique of endoscopic lower ureterectomy by intussusception is described and the literature is reviewed. The technique has been used successfully in 2 patients with papillary neoplasms limited to the renal pelvis.


Asunto(s)
Neoplasias Renales/cirugía , Uréter/cirugía , Cistoscopía/métodos , Endoscopía , Humanos , Médula Renal/cirugía , Masculino , Persona de Mediana Edad , Nefrectomía/métodos , Cateterismo Urinario
3.
Phys Rev Lett ; 102(9): 097001, 2009 Mar 06.
Artículo en Inglés | MEDLINE | ID: mdl-19392554

RESUMEN

We report on small-angle neutron scattering studies of the intrinsic vortex lattice (VL) structure in detwinned YBa2Cu3O7 at 2 K, and in fields up to 10.8 T. Because of the suppressed pinning to twin-domain boundaries, a new distorted hexagonal VL structure phase is stabilized at intermediate fields. It is separated from a low-field hexagonal phase of different orientation and distortion by a first-order transition at 2.0(2) T that is probably driven by Fermi surface effects. We argue that another first-order transition at 6.7(2) T, into a rhombic structure with a distortion of opposite sign, marks a crossover from a regime where Fermi surface anisotropy is dominant, to one where the VL structure and distortion is controlled by the order-parameter anisotropy.

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