Josephson Current in the Presence of a Precessing Spin

The Josephson current in the presence of a precessing spin between various types of superconductors is studied. It is shown that the Josephson current flowing between two spin-singlet pairing superconductors is not modulated by the precession of the spin. When both superconductors have equal-spin-triplet pairing state, the flowing Josephson current is modulated with twice of the Larmor frequency by the precessing spin. It was also found that up to the second tunneling matrix elements, no Josephson current can occur with only a direct exchange interaction between the localized spin and the conduction electrons, if the two superconductors have different spin-parity pairing states.Comment: 5 pages, 1 figur

Fine structure of ultimobranchial follicles in the thyroid gland of the rat

The mature ultimobranchial follicle of the rat consists of two or more layers of cells (U cells) surrounding a lumen containing cell debris. The ultrastructure of the outer, or basal, U cell is characterized by the presence of half desmosomes on the basal plasma membrane and pinocytotic vesicles near it, by little granular reticulum but an abundance of free ribosomes, by clusters of fibrils connected to desmosomes and possibly free in the cytoplasm. The cell ages by accumulation of clusters of fibrils and it undergoes differentiation to form more apical U cells which contain fewer ribosomes and have fibrils dispersed in the cytoplasm. The apical U cell is desquamated into the lumen and ultimately becomes a carcass containing a dense matting of fibers and vacuoles containing a reticulated material resembling that in the lumen. U cells are observed associated with typical thyroid epithelium in the thyroid of the newborn rat in relatively large follicles containing colloid and desquamated cells. They also form rods of cells in the very young rat. Mixed follicles containing both U cells and typical thyroid epithelium occur at all ages. Copyright © 1971 Wiley‐Liss, Inc.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Postnatal development and properties of ultimobranchial follicles in the rat thyroid

Mature ultimobranchial follicles in the Fischer rat thyroid are characterized by being lined by two or more layers of cells (U cells) and by having an abundance of desquamated cells in the lumen. Such follicles, of variable size and shape, were found in almost every lobe in rats at least 30 days old. They were usually in the interior of the lobe in contact with perivascular connective tissue. Ultimobranchial follicles with multiple layers of cells were not observed in the two‐day‐old rat indicating that these follicles are an example of postnatal development. The most common precursor in the rat was a follicle, relatively large compared with the usual thyroid follicle, containing some cells or debris. Other precursor structures included narrow tubes, sheets or spheroids of cells characteristically having little cytoplasm. Intermedlate forms between these precursors and mature ultimobranchial follicles were recognized. Cells were desquamated while nucleated, and, later, the nuclei disappeared. Thus, in some follicles non‐nucleated debris accumulated. Many follicles were composed of mixed populations of cells, both typical thyroid epithelium and U cells. The relative abundance of the two cell types varied markedly as did the proportions of colloid and cell debris. Copyright © 1971 Wiley‐Liss, Inc.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Ultrastructure of the thyroid gland of the cream hamster

The typical thyroid epithelium of the cream variant of the Syrian hamster differs from that of other common mammalian species. One obvious difference noted by light microscopy is that the cells contain numerous PAS‐positive granules apical to the nucleus. By electron microscopy these granules are dense granules resembling lysosomes. The cells have exceptionally long microvill and numerous junctions and interdigitations of lateral plasma membranes with those of their neighbors. Many organelles in the cells are stratified rather than arranged at random. In addition to the dense granules and centrioles, the Golgi apparatus is usually located at the level of the apical end of the nucleus. The granular reticulum is primarily in the basal half of the cell, although some is apical. Microtubules are especially abundant and are located ainly close to the lateral surfaces and around the nucleus, although some are near apical or basal plasma membranes. The microtubules frequently appear to be in contact with mitochondria and dense granules, but their role in the positioning or stratification of organelles is uncertain. Copyright © 1971 Wiley‐Liss, Inc.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Histological changes in TSH-dependent tumours of the thyroid gland during serial transplantation in Fischer 344 rats

Transplantable tumours were induced in the thyroids of Fischer 344 rats fed thiouracil (TU) in a moderately low iodine diet for 8–13 months. Pieces of hyperplastic thyroid were implanted subcutaneously into rats fed a TU containing diet. Almost all implants gave rise to very small vascularized transplants but there were three significantly larger, pieces of which were transplanted again and gave rise to the tumour lines. From the third transplantation generation on, pieces of tumours were implanted into rats treated to have elevated circulating thyrotropin and a group fed a high iodine diet. With some exceptions, the implants grew only in rats fed the TU or a low iodine diet and yielded TSH-dependent tumours. Almost all the tumours observed initially were papillary, and most of the remainder had colloid-filled follicles bounded by columnar cells. One line of tumours was of the latter type for eight generations. The others had more complex histories, in which there were sublines that were papillary for eight or nine generations, whereas, others became progressively more cellular or follicular, and more heterogenous with respect to histological types present per section at rates that varied with the subline. The large number of population doublings necessary to make a one gram tumour from a single original tumour cell indicates that the cells of dependent papillary tumours were immortalized

Fine structure of colloid cells in the thyroid gland

Thin sections of colloid cells in the thyroid gland of the C3H mouse were observed with an electron microscope. There appeared to be 2 main kinds of colloid cells. In the first, the clear appearance of the cytoplasm is due to the presence of a very dilated cisterna of the granular reticulum in an otherwise normal appearing cell. In the second, the plasma membrane of the cell appeared disrupted and there was extensive replacement of the cytoplasm by material resembling colloid. No information is available yet on the origin of colloid cells but it is quite clear that they are not specific for thyroiditis or other recognized diseases of the thyroid gland. © 1970 by The Endocrine Society.SCOPUS: ar.jinfo:eu-repo/semantics/publishe