Search

This article will first briefly review the impressive advancements made in high-temperature superconductivity (HTS) before the arrival of room-temperature superconductivity (RTS). Accompanying the advancements made in superconductivity science and technology over the last century, a solid experimental framework concerning the search, development, and even authentication of new discoveries has been established. All these can serve as valuable references in the infancy of RTS research. In this spirit, we will comment on the current status of rare-earth hydride RTS and present our preliminary negative results on Lu-N-H and LK-99, the two most studied materials in the search for RTS in the last few months, although several more reports of negation than affirmation have appeared.

Abstract: We have studied optical properties of opaline thin films grown by the vertical deposition method. The opaline films under study were three-dimensional close-packed arrangements of a-SiO2 spheres. The fcc domains, which are of 10–50 μm in size and separated by cracks, were seen in FE-SEM images. Analysis of angle-resolved transmissivity of opaline films shows that they act as three-dimensional photonic crystals. Photonic stop-bands were observed and attributed to the {111} family of crystallographic planes. Crystallographic structure of the films was characterized as twinned fcc, in which twins are spatially separated by cracks.

Aims/hypothesis. We examined the prevalence of diabetes and investigated the characteristics of subjects diagnosed by the American Diabetes Association and the World Health Organization criteria. Methods. A total of 1235 Japanese-Americans living in Hawaii and Los Angeles was studied. Of the subjects 114 were classified as previously diagnosed as having diabetes. A 75-g glucose tolerance test was given to the rest of the subjects. Results. When abnormal glucose tolerance was diagnosed by the American Diabetes Association criteria, it was possible to identify only 40 % of diabetic subjects who had not been previously diagnosed compared with the current World Health Organization criteria based on a glucose tolerance test. In addition, the subjects identified by the American Diabetes Association criteria had higher glucose concentrations and had less insulin secretory capacity and they were in need of intensive treatment for diabetes. On the other hand, the subjects not diagnosed by the American Diabetes Association criteria alone were those whose glucose tolerance would be more likely to improve with lifestyle modification. Conclusion/interpretation. It might be better to use the fasting plasma glucose criterion advocated by the American Diabetes Association in combination with a glucose tolerance test after taking a detailed medical history. To reduce the number of subjects requiring the glucose tolerance test, priority should be given to subjects with impaired fasting glucose (6.1 ≤ fasting plasma glucose < 7.0 mmol/l). [Diabetologia (1999) 42: 1168–1170]Aims/hypothesis. We examined the prevalence of diabetes and investigated the characteristics of subjects diagnosed by the American Diabetes Association and the World Health Organization criteria. Methods. A total of 1235 Japanese-Americans living in Hawaii and Los Angeles was studied. Of the subjects 114 were classified as previously diagnosed as having diabetes. A 75-g glucose tolerance test was given to the rest of the subjects. Results. When abnormal glucose tolerance was diagnosed by the American Diabetes Association criteria, it was possible to identify only 40 % of diabetic subjects who had not been previously diagnosed compared with the current World Health Organization criteria based on a glucose tolerance test. In addition, the subjects identified by the American Diabetes Association criteria had higher glucose concentrations and had less insulin secretory capacity and they were in need of intensive treatment for diabetes. On the other hand, the subjects not diagnosed by the American Diabetes Association criteria alone were those whose glucose tolerance would be more likely to improve with lifestyle modification. Conclusion/interpretation. It might be better to use the fasting plasma glucose criterion advocated by the American Diabetes Association in combination with a glucose tolerance test after taking a detailed medical history. To reduce the number of subjects requiring the glucose tolerance test, priority should be given to subjects with impaired fasting glucose (6.1 ≤ fasting plasma glucose < 7.0 mmol/l). [Diabetologia (1999) 42: 1168–1170]