Brain tumors induced in rats by human adenovirus type 12

Oncogenesis of human adenovirus type 12 in the brain of rats was examined. Newborn rats of Sprague-Dawley and Donryu&#12288;strains were injected intracranially with human adenovirus type 12.&#12288;The incidence of intracranial tumors was 91% (30/33) in SpragueDawley&#12288;and 56% (14/25) in Donryu rats. Except for one tumor nodule&#12288;located in the parietal cortex of a Sprague.Dawley rat, all tumors&#12288;developed in the paraventricular areas or in the meninges. Tumors were quite similar histologically to those induced in hamsters and&#12288;mice resembling the undifferentiated human brain tumors such as medulloblastoma,&#12288;ependymoblastoma and embryonic gliomas. From&#12288;the histological features and primary sites of tumor development, it is&#12288;suggested that the tumors in the brain of rats induced by adenovirus type 12 originate from the embryonic cells in the&#12288;paraventricular area&#12288;and also from the undifferentiated supporting cells of the peripheral&#12288;nerves in the&#12288;leptomeninges.</p

Eliciting the aspects of local lives in a historical district as perceived by visitors

This study aims to extract the elements that visitors could focus on in a historical district as the aspects of the local lives and visitors’ evaluation of them by analyzing respondents’ open-ended responses about things that they thought attractive in the targeted historical districts and objects through which they sensed the lives of the locals. The visitors are grouped based on their ratings of their overall impression of the historical districts on Semantic Differential Scales, and comparison between the open-ended responses of the two groups is also attempted to obtain insights into the effects of their visiting experiences. The results imply the importance of visitors’ perception of the ways in which the districts are utilized. The areas that the respondents visited are also suggested to relate to their views of the district’s features, including the facets of the local lives

A new method for monitoring and removing SuperDARN radar DC offsets

DC offsets in quadrature outputs (I/Q signals) pertinent to the SuperDARN HF radars can cause problems in determining and analysing auto-correlation functions, cross-correlation functions and raw time series data if they are not negligible. We have developed a new code to monitor and remove DC offsets. To obtain correct DC offset levels and noise levels, the offsets can be best removed using I/Q signals during the receive-only period, i.e., during each clear frequency search stage. We have implemented the new code in the current radar operating system, installed it at the SENSU Syowa radars, and have been obtaining and removing DC offset values continuously since October 2001

On the histo-morphological changes of transplantable tumors.

1. When chicken sarcoma virus is serially inoculated on the mouse brain, it loses its carcinogenecity, but when it is inoculated on young chicken, granuloma develops in the liver and lung. When this granuloma is transplanted on adult chicken, a transplantable fibrosarcoma is obtained. 2. According to literature, the originaltumor of the Brown-Pearce cancer is a basal cell cancer, but that imported to Japan in 1953 presented a histological picture of carcinosarcoma. The metastasized tumor of the eye presents a purely cancer tissue, but when this is inoculated on the testis, carcinosarcoma is reproduced. It is therefore considered that the mother cell of the sarcoma is of host origin. 3. MY sarcoma is not a sarcoma, but is a spindle cell cancer. It might be a sarcoma which transformed into a cancer during serial transplantation, but perhaps it was originally a cancer but had been erroneously diagnosed as sarcoma. 4. The tumors we obtained by means of the feeding tests of Yoshida tumor all developed at organs other than those of the digestive tract. They are chiefly reticulo-sarcoma, but others which develop are malignant granuloma in the liver and lung, malignant adenoma in the kidney, papilloma of pelvis, and ependymoma in the cerebral ventricle. Since the discovery of the Yoshida tumor in 1943, serial transplantation has been conducted for 19 years with this tumor not only in Japan but also in foreign countries, but there has been no report to this date that a transformed strain has developed by cell transplantation. It therefore must be considered that the carcinogenesis observed in our feeding tests is a carcinogenesis due to a mechanism completely unlike that of cell transplantation. It has been confirmed by electron microscopy that in the early stage of transplantation of this tumor into the abdominal cavity there was an additional tumor growth due to the anaplastic proliferation of serous cells. 5. During the serial transplantation of viral tumors and/or virus dependent tumors, the tumor sometimes undergoes a morphological change. Though the cause of this is not yet sufficiently elucidated, it is suspected that there is some relationship with virus in the wide sense.</p

Role of bias and tunneling asymmetries in nonlinear Fermi-liquid transport through an SU(NN) quantum dot

We study how bias and tunneling asymmetries affect nonlinear current through a quantum dot with $N$ discrete levels in the Fermi liquid regime, using an exact low-energy expansion of the current derived up to terms of order $V^3$ with respect to the bias voltage. The expansion coefficients are described in terms of the phase shift, the linear susceptibilities, and the three-body correlation functions, defined with respect to the equilibrium ground state of the Anderson impurity model. In particular, the three-body correlations play an essential role in the order $V^3$ term, and their coupling to the nonlinear current depends crucially on the bias and tunnel asymmetries. The number of independent components of the three-body correlation functions increases with $N$ the internal degrees of the quantum dots, and it gives a variety in the low-energy transport. We calculate the correlation functions over a wide range of electron fillings of the Anderson impurity model with the SU($N$) internal symmetry, using the numerical renormalization group. We find that the order $V^3$ nonlinear current through the SU($N$) Kondo state, which occurs at electron fillings of $1$ and $N-1$ for strong Coulomb interactions, significantly varies with the three-body contributions as tunnel asymmetries increase. Furthermore, in the valence fluctuation regime toward the empty or fully occupied impurity state, a sharp peak emerges in the coefficient of $V^3$ current in the case at which bias and tunneling asymmetries cooperatively enhance the charge transfer from one of the electrodes.Comment: 18 pages, 13 figures. Typos have been correcte

First mesopause temperature measurements using sodium lidar observations in the Antarctic region

The mesopause temperature structure was observed using a sodium temperature lidar system at Syowa Station (69°00\u27 S, 39°35\u27 E), beginning in February 2000. The laser transmitter was newly developed and included two injection-seeded Nd: YAG lasers. Regular observations were performed using the two-frequency technique as demonstrated by C.Y. She et al. (Geophys. Res. Lett., 17, 929, 1990), with a spatial resolution of about 1 km and a temporal resolution of 6 min. The temperature structures of the 85km to 105km region of the upper atmosphere were measured by Na D_2 Doppler profile-fitting as well as the two-frequency technique. Temperatures derived from the two techniques agreed well and were consistent with the MSIS 90 model temperature structure. Night-time temperature variations over a 15-hour period were measured in May 2000. A large temperature fluctuation with an interval of about 4 hours, and an amplitude of 60 K (probably caused by gravity waves) was observed. From the average night temperature profile, the mesopause was determined to be located at 102km, and have a temperature of 180K. These values are similar to winter values observed in the northern hemisphere

Stable isotope study of the hotsprings and volcanoes of Hokkaido, Japan

Stable isotope ratios of hydrogen, oxygen, carbon and sulfur of precipitation, thermal and mineral waters, and volcanic gases were measured. The isotopic data combined with chemical and geological information were discussed in terms of origin and evolution of the hotsprings and volcanic gases. The hotsprings along the Uchiura Bay, Oshima Peninsula are mostly near-neutral NaCl-type thermal water and may be divided into three groups : (1) thermal waters isotopically similar to the precipitation of this area, (2) those similar in D/H to the local meteoric waters but enriched by 2 to 3‰ in (18)O compared to the latter, and (3) those enriched significantly in both D and (18)O relative to the local meteoric waters. The first and second types of thermal water probably form from local meteoric water which percolates through "Green Tuff" formations and acquires dissolved chemicals from them. However, high salt concentration and the oxygen isotope shift (thesecond type) may imply that the NaCl-type water of volcanic origin might be involved. On the other hand, the waters of the third group can be explained by mixing of modern sea water into the second type thermal water (in case of Yachigashira) or by incorporation of fossil sea water of Tertiary origin into modern meteoric water (Nigorigawa). Except for Esan, Noboribetsu and Atosanupuri volcanic systems, waters from all the hotsprings and volcanic fumaroles associated with Quaternary volcanic rocks are meteoric in origin. Thermal waters at Esan, Noboribetsu and Atosanupuri have δD = -30～-50 and δ(18)O = -1～+ 3‰ and are enriched in D and (18)O relative to local meteoric water of the respective area. The origin of these waters and the mechanism (s) controlling the isotope ratios could not be made clear by the present study. Interesting is the finding that at Esan, Noboribetsu and Atosanupuri, thermal waters are enriched in D and (18)O relative to near-by fumarolic gases. The enrichment factor is 18 to 26‰ for hydrogen and 4 to 6‰ for oxygen, implying that more than one stages of liquidvapor separation are taking place in underground hydrothermal systems