Cognitive radio network in vehicular ad hoc network (VANET): a survey

Cognitive radio network and vehicular ad hoc network (VANET) are recent emerging concepts in wireless networking. Cognitive radio network obtains knowledge of its operational geographical environment to manage sharing of spectrum between primary and secondary users, while VANET shares emergency safety messages among vehicles to ensure safety of users on the road. Cognitive radio network is employed in VANET to ensure the efficient use of spectrum, as well as to support VANET’s deployment. Random increase and decrease of spectrum users, unpredictable nature of VANET, high mobility, varying interference, security, packet scheduling, and priority assignment are the challenges encountered in a typical cognitive VANET environment. This paper provides survey and critical analysis on different challenges of cognitive radio VANET, with discussion on the open issues, challenges, and performance metrics for different cognitive radio VANET applications

Human Extravillous Trophoblasts Penetrate Decidual Veins and Lymphatics before Remodeling Spiral Arteries during Early Pregnancy

<div><p>In humans, the defective invasion of the maternal endometrium by fetal extravillous trophoblasts (EVTs) can lead to insufficient perfusion of the placenta, resulting in pregnancy complications that can put both mother and baby at risk. To study the invasion of maternal endometrium between (W)5.5–12 weeks of gestation by EVTs, we combined fluorescence in situ hybridization, immunofluorescence and immunohistochemistry to determine the presence of (male) EVTs in the vasculature of the maternal decidua. We observed that interstitial mononuclear EVTs directly entered decidual veins and lymphatics from W5.5. This invasion of decidual veins and lymphatics occurred long before endovascular EVTs remodelled decidual spiral arteries. This unexpected early entrance of interstitial mononuclear EVTs in the maternal circulation does not seem to contribute to the materno-placental vascular connection directly, but rather to establish (and expand) the materno-fetal interface through an alternative vascular route.</p></div

Human extravillous trophoblast cells invade decidual veins and lymphatics early during first trimester.

<p>(A) Histological sections of decidua basalis from a (mosaic) Klinefelter syndrome (47,XXY and 46, XY) pregnancy at W8.4. Left panels show low magnifications of same section immunostained for pKRT and PECAM1 (top) and chrX/chrY FISH (bottom). Middle-left and middle-right panels are magnifications of the (numbered) dashed boxes in the left panels. Right panels are magnifications of the dashed boxes in the middle-right panels. White arrowheads point to XXY fetal EVTs. (B) Histological sections of decidua basalis at W7.2, W8.4 and W10 immunostained for pKRT, PDPN and PECAM1 (left panels). FISH for chrX and chrY (right) was performed in the in the pKRT/PDPN/PECAM1-stained sections. White arrows point to EVTs invading the lymphatic vessels. All scale bars are depicted.</p

Terminal differentiation of Schwann cells in the cochlear nerve.

<p>(A–C) Deconvoluted confocal images of the cochlear nerve at W9 showing TUBB3 (A, red), S100B (B, green), and the merged image with DAPI (C). (D–G) Deconvoluted confocal images of an axial transection of the cochlear nerve at W22 showing DAPI (D), TUBB3 (E), S100B (F) and the merged image (G). The upper inset in G shows a high-magnification of TUBB3+ cochlear nerve fibers each enveloped by S100B+ Schwann cells, the lower inset shows a Remak bundle. (H–K) Deconvoluted confocal images of a sagittal transection of the cochlear nerve at W22 showing DAPI (H), TUBB3 (I), MBP (J) and the merged image (K). The inset shows a high-magnification view of a myelinated nerve fiber. Scale bar = 10 µm or 1 µm (insets in G and K).</p

Myelination of spiral ganglion neurons at W22.

<p>(A–E) Confocal images of a spiral ganglion in the middle turn of a cochlea at W22 showing DAPI (A), TUBB3 (B), PRPH (C), MBP (D) and the merged image (E). The spiral ganglion is delineated by the dotted line. (F–J) Confocal images of an axial transection of the cochlear nerve at W22 showing DAPI (F), TUBB3 (G), PRPH (H), MBP (I) and the merged image (J). (K–O) Deconvoluted confocal images of an axial transection of the cochlear nerve at W22 showing DAPI (K), TUBB3 (L), PRPH (M), MBP (N) and the merged image (O). Insets show TUBB3 (left), PRPH (middle) and the merge with MBP and DAPI (right) in high-magnifications examples of PRPH−/TUBB3+/MBP+ cochlear nerve fibers (upper inset) and PRPH+/TUBB3+/MBP+ cochlear nerve fibers (lower inset). Scale bar = 20 µm or 1 µm (insets in O).</p

Human EVTs penetrate decidual veins early during first trimester (W5.5-W7.5).

<p>(A) Histological sections of decidua basalis at W5.5 used for Azan staining (left panel), immunostained for pKRT and ACTA2 (left-middle panel) and immunostained for pKRT and PECAM1 (right-middle panel). FISH for chrX/chrY (right) was performed in the pKRT/PECAM1-stained sections. White arrows indicate male EVTs invading veins. The bottom row shows magnifications of the dashed boxes in the top row. (B) Consecutive sections of W5.5 decidua basalis were immunostained for pKRT/PECAM1. (C) FISH for chrX and chrY (right panels) magnifications are shown for the section in dashed box. White arrows point to male EVTs penetrating a decidual vein. (D) Histological sections of decidua basalis at W7.2 used for Azan staining (left panel), immunostained for pKRT and PECAM1 (left-middle panel). FISH for chrX/chrY (right panels) was performed in the pKRT/PECAM1-stained sections. The most right panel shows a magnification of the dashed box. White arrows indicate male EVTs invading veins. (E) Percentage of invaded decidual veins per total veins encountered per histological section (n) between W5.5-W12. Results are sown as mean ± standard deviation. All scale bars are depicted.</p

Human EVTs in the vicinity of arteries early during first trimester (W5.5).

<p>Histological sections of W5.5 decidua basalis showing decidual arteries. Consecutive sections were used for Azan staining (left panel), immunostained for pKRT and ACTA2 (left-middle panel) and immunostained for pKRT and PECAM1 (right-middle panel). FISH for chrX and chrY (right panel) was performed in the pKRT/PECAM1-stained sections. The (middle and) bottom rows show magnifications of the (numbered) dashed boxes in the top rows. White arrows depict male EVTs. All scale bars are depicted.</p

PGCs expressed SOX10, SOX9 and S100B in the W10.4 human fetal cochlea.

<p>(A–B) Confocal images of the lower basal turn of a W10.4 cochlea immunostained for SOX10 and SOX10 merged with DAPI. (C–D) Confocal images of an adjacent section immunostained for SOX9 and SOX9 merged with DAPI. (E–G) Confocal images of the lower basal turn of a W10.4 cochlea immunostained for S100B (E) and TUBB3 (F) and the merged image with DAPI (G). (H–J) High-magnification view of the center of the spiral ganglion. (K–M) Detail of the peripheral processes at their distal end. Abbreviations: cd, cochlear duct; SG, spiral ganglion. Scale bar = 50 µm (A–G) or 20 µm (H–M).</p

Human extravillous trophoblast cells in decidua between W8-W12.

<p>(A) Histological sections of decidua basalis at W8.4 used for Azan staining (left panel), immunostained for pKRT and PECAM1 (left-middle panel). FISH for chrX/chrY (right panels) was performed in the pKRT/PECAM1-stained sections. The most right panel shows a magnification of the dashed box. White arrows indicate male EVTs invading veins. (B) Histological sections of decidua basalis at W10 used for Azan staining (left panel), immunostained for pKRT and ACTA2 (left-middle panel) and immunostained for pKRT and PECAM1 (right-middle panel). FISH for chrX/chrY (right) was performed in the pKRT/PECAM1-stained sections. White arrows indicate male EVTs. Low magnifications are shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0169849#pone.0169849.s002" target="_blank">S2 Fig</a>. (C) Histological sections of W10 and W12 decidua basalis showing remodeled and unremodelled arteries. Consecutive sections were immunostained for pKRT and ACTA2 (left panels) and immunostained for pKRT and PECAM1 (middle panels). FISH for chrX and chrY (right panels) was performed in the pKRT/PECAM1-stained sections. The bottom rows show magnifications of the dashed boxes in the top rows. All scale bars are depicted.</p

Immature Schwann cells along the peripheral processes express NGFR.

<p>(A–D) Confocal images of the lower basal turn of a cochlea at W9 showing DAPI (A), TUBB3 (B) and NGFR (C) and the merged image (D). The spiral ganglion is delineated by the dotted line. The asterisk marks two NGFR+ cells in the center of the spiral ganglion. (E–I) Confocal images of the lower basal turn of a cochlea at W10.4 showing DAPI (E), TUBB3 (F), SOX10 (G) and NGFR (H) and the merged image (I). The spiral ganglion is delineated by the dotted line. The inset shows a deconvoluted, high-magnification view of TUBB3 and NGFR at the distal tips of the peripheral processes. Abbreviations: SG, spiral ganglion. Scale bar = 50 µm or 5 µm (inset in I).</p