Low-loss terahertz metamaterial from superconducting niobium nitride films.

This paper reports a type of low Ohmic loss terahertz (THz) metamaterials made from low-temperature superconducting niobium nitride (NbN) films. Its resonance properties are studied by THz time domain spectroscopy. Our experiments show that its unloaded quality factor reaches as high as 178 at 8 K with the resonance frequency at around 0.58 THz, which is about 24 times that of gold metamaterial at the same temperature. The unloaded quality factor keeps at a high level, above 90, even when the resonance frequency increases to 1.02 THz, which is close to the gap frequency of NbN film. All these experimental observations fit well into the framework of Bardeen-Copper-Schrieffer theory and equivalent circuit model. These new metamaterials offer an efficient way to the design and implementation of high performance THz electronic devices.

[Studies on the location of eight lectins in breast carcinoma].

100 cases of breast carcinoma were studied with lectin affinitive histochemistry technology. The result showed that Ricinus comunis agglutinin (RCA1) was located in almost all intraductal carcinomas but one, while the positive rates in the other types were obviously low (P less than 0.05). The positive rate of Ulex europaeus agglutinin-I (UEA1) in well-differentiated types was higher than that in poorly-differentiated ones (P less than 0.05). The location of Peanut agglutinin (PNA), Bandeiraea Simplicifolia (BSL) and UEA1 in breast carcinomas exhibited some regularity and it might be useful in understanding the differentiation of breast carcinomas. No relationship between changes of the eight lectins and metastases in axillary lymph nodes was observed, but the authors considered that PNA-affinitive histochemistry was beneficial to the detection of micrometastases in lymph nodes.

Giant cell tumors of bone. An immunohistochemical study.

Immunohistochemical study of giant cell tumor of bone (GCT) was carried out utilizing a panel of monoclonal antibodies including those against lysozyme, alpha-antichymotrypsin (AACT), vimentin (Vim), M718, HLA-DR, S-100 protein, epithelial membrane antigen (EMA), leukocyte common antigen (LCA), KB90, factor VIII related antigen (F VIII) against stromal cells and giant cells in 20 cases of GCT, with one case of prolonged continuously cultured cells GCT (GT 15). The results showed that stromal cells could be divided into two subgroups. Mesenchymal stromal cells labelled only with vimentin and were regarded as being derived from undifferentiated mesenchymal cells of bone marrow, while macrophage-like stromal cells labelled with antigens and were found to be present in mononuclear phagocytes. We believe this to be the first report that some stromal cells reacted positively with S-100 protein. Multinucleated giant cells were AACT and M718 positive, indicating their close relationship to macrophage-like stromal cells. The prolonged cultured cells accepted labelling with vimentin only indicating that all macrophage-like stromal cells disappeared after several subcultures and the only cells that could continue to be subcultured were the mesenchymal stromal cells.

Light- and electron-microscopic study of M. leprae-infected armadillo nerves.

Lesions in peripheral nerves of armadillos experimentally infected with Mycobacterium leprae were studied by light- and electron-microscopy. Bacilli could be found clearly inside axons of unmyelinated nerve fibers. Heavily bacillated Schwann cells were seen embracing unmyelinated axons with interrupted cytoplasmic membranes. This indicated the initiation of rupture of those cells which were responsible for the liberation of bacilli into the axons. The nerve lesions were divided into three grades according to their severity: grade I showed lesions focalized in the perineurium; grade II lesions were scattered inside nerve tissue; and in grade III lesions the nerve tissues were diffusely affected. No regressive changes, such as fibrosis or scar formation, were seen in the nerve lesions. Bacillated macrophages were not as foamy as those of human lesions, indicating that these bacillated cells were younger or more easily disrupted with a higher turnover than the cells in human lesions. This would promote the spread of lesions in armadillos, and would explain the less foamy appearance of the cells. We found bacilli inside lymphatics surrounding the nerves, substantiating the opinion that lesions spread to peripheral nerves not only by a hematogenous route but also by the lymphatics.

[Epithelioid sarcoma--immunohistochemical and ultrastructural study].

Five cases of epithelioid sarcoma are reported, of which four were studied by immunohistochemistry and one by electron microscopy. Immunohistochemically, the results of cytokeratin showed that these four cases were positive to different degrees by polyclonal cytokeratin and three out of four revealed positive results with low molecular weight cytokeratin monoclonal antibody. Two cases were positive with carcinoembryonic antigen and the other two were negative. The immunohistochemical stain was helpful for differential diagnosis from other sarcomas, such as malignant fibrous histiocytoma and rhabdomyosarcoma. By electron microscopy, tumor cells could be divided into light and dark cells which possessed more or less cell organelles, intermediate microfilaments in the cytoplasm and numerous pinocytic vesicles lying along the cell membrane. The occasional presence of poorly developed desmosomes or the absence of tonofibril bundles and glandular structures can rule out the diagnosis of carcinoma. One of these cases was originally diagnosed as metastatic carcinoma to the skin by light microscopy, which was refuted by electron microscopy, and the keratin positive reaction by immunohistochemistry was helpful for the diagnosis of epithelioid sarcoma. Therefore, the authors suggest that immunohistochemical and electron microscopic studies be used for diagnosing difficult cases of epithelioid sarcoma. From our observation, we consider that the cells of epithelioid sarcoma may derive from undifferentiated mesenchymal cells possessing the potentials of differentiating into synovioblasts, histiocytes or fibroblasts.

[Discovery and electron microscopic observation on unusual intranuclear inclusion bodies of breast carcinoma].

Unusual intranuclear inclusion bodies in one case of breast carcinoma discovered and studied by electron microscope is reported. The ultrastructural feature of these inclusion bodies is very characteristic and has not been reported previously. They presented with unequal sizes, location at the margin of nuclei, and frequent separation from the nuclear chromatin by a single thin membrane. These inclusion bodies can be divided into two kinds: one with granular central portion surrounded by numerous radiating flagella-like filaments, the other assuming concentric laminated arrangements. There are transitional forms between them. The nature of these intranuclear inclusion bodies are discussed.

[Ultrastructural and immunohistochemical observations on alveolar rhabdomyosarcoma].

One case of alveolar rhabdomyosarcoma appearing like an undifferentiated tumor by light microscopy is reported. Specific ultramicroscopic features of sarcomere containing Z line structures, thick and thin myofilaments with hexagonal arrangements in the cross section were noted in the cytoplasm of some individual malignant cells, thus establishing the diagnosis of rhabdomyosarcoma. Some of the tumor cells were positive to peroxidase-anti-peroxidase (PAP) immunohistochemical stain of anti-serum by anti-myosin. In the present paper, the ultrastructural features and differential diagnosis of poorly differentiated rhabdomyosarcoma are also discussed.