1,847 research outputs found
Development of the myelin sheath of the hypogastric nerves in a human foetus aged 23 weeks
The formation of the myelin sheath of the human hypogastric nerves was studied
by electron microscopy in a foetus of 23 weeks of postovulatory age (220 mm
C-R length). In the investigated foetus the hypogastric nerves were mainly composed
of bundles of unmyelinated fibres. The myelinated fibres were seen to be
at different stages of myelination. Well myelinated fibres had thick compact
laminated myelin. The number of myelin lamellae on a single fibre was 22
Early development of the human palate in stages 16 and 17
A study was performed on 12 human embryos at developmental stages 16 and
17 (6th week). In the investigated embryos the primary palate is formed from
medial nasal, lateral nasal, and maxillary processes. The medial and lateral nasal
processes merge and form the nasal fin at stage 16. This fin regresses and at
stage 17 and persists as the oronasal membrane. The primordia of the secondary
palate appear at stage 17. (Folia Morphol 2011; 70, 1: 29-32
Schwann units in the human foetal phrenic nerve
In three human foetuses aged 15, 17, and 23 weeks the number of axons
surrounded by single Schwann cells was counted. These Schwann cell/axon complexes
form the Schwann units. The largest Schwann units in the foetus aged
15 weeks contained 232 axons, in the foetus of 17 weeks the number was
140 and in the foetus of 23 weeks the largest units contained 65 axons
Conceptual design of elliptical cavities for intensity and position sensitive beam measurements in storage rings
Position sensitive beam monitors are indispensable for the beam diagnostics
in storage rings. Apart from their applications in the measurements of beam
parameters, they can be used in non-destructive in-ring decay studies of
radioactive ion beams as well as enhancing precision in the isochronous mass
measurement technique. In this work, we introduce a novel approach based on
cavities with elliptical cross-section, in order to compensate for existing
limitations in ion storage rings. The design is aimed primarily for future
heavy ion storage rings of the FAIR project. The conceptual design is discussed
together with simulation results.Comment: Added definition of Uv and Pdiss in the introduction section. Added
Mode numbering in table 1 and figure 1 for more clarity. Corrected one wrong
figure reference. Other minor typo correction
Differentiation of the facial-vestibulocochlear ganglionic complex in human embryos of developmental stages 13–15
A study was made on 18 embryos of developmental stages 13–15 (5th week).
Serial sections made in horizontal, frontal, and sagittal planes were stained
with routine histological methods and some of them were treated with silver.
In embryos of stage 13, the otic vesicle is at the rhombomere 5, and close to
the vesicle is the facial-vestibulocochlear ganglionic complex in which the geniculate,
vestibular, and cochlear ganglion may be discerned. These ganglia are
well demarcated in embryos of stage 14. In the last investigated stage (15th)
the nerve fibres of the ganglia reach the common afferent tract
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