Spontaneous and induced hyperplasia and neoplasia in the mouse lung.

,SINCE Livingood (1896) first described a spontaneous pulmonary tumour in a mouse, much has been written on the histogenesis of this common tumour, vet it is still difficult to decide whether an early lesion should be classified as hyperplastic or neoplastic. Since the introduction of line-bred strains of mice by Strong (1936) and their general use by research workers, genetic differences in susceptibility have been extensively investigated by Heston (1940) and manv others. It is accepted that the susceptibility to spontaneous development of pulmonary tumours is high in A Strain and low in C57 Black, but that there is no essential difference between the type or range of tumours seen in different strains (Stewart, 1953). As to the sites of origin and distribution of these tumours, most authors describe them as subpleural and as originating in the alveolar epithelium. As far as we know, there has been no evidence as to localising factors which cause one alveolus rather than another to develop neoplastic growth

Solar sailing - mission opportunities and innovative technology demonstration

Solar sailing is a unique and elegant form of propulsion that transcends reliance on reaction mass. Rather than carrying propellant, solar sails acquire momentum from photons, the quantum packets of energy from which sunlight is composed. In addition, since solar sails are not limited by reaction mass, they can provide continual acceleration, limited only by the lifetime of the sail film in the space environment. Therefore, solar sails can expand the envelope of possible missions, enabling new high-energy mission concepts that are essentially impossible with conventional reaction propulsion, and enhancing current mission concepts by lowering launch mass and reducing trip times

Lung tumours in mouse embryo homografts.

IN a previous communication the induction of tumours in BALB/c mouse embryo homografts has been described (Peacock, 1962). The tumours arose in a variety of tissues exposed to carcinogens of the polycyclic aromatic hydrocarbon series. The most frequently recorded tumour was a well differentiated squamous carcinoma. A few sarcomas were seen, alone, or accompanying a carcinoma. Adenomas were also present but were not considered as proof of carcinogenic action due to their occurrence in control implants as well. The high incidence of squamous tumours in embryo lung implants was surprising as the commonly occurring tumour of lung in adult mice is an adenoma. In an extensive review of the literature Shimkin (1955) records only eight spontaneously occurring epidermoid tumours of lung in adult mice. The histogenesis of these squamous tumours of embryo lung has now been studied through the re-examination of the original material and by further experiments. Hydrocarbon induced tumour

A Short Term Test for Carcinogenicity: Mouse Embryo Tissue Homografts in BALB/c Strain Mice

RoUS AND SMITH (1945) drew attention to the fact that embryo skin of BALB/c strain mice if minced and inoculated into the thigh muscle of adults of the same strain would survive and differentiate, and that by including methylcholanthrene in the inoculum, squamous carcinomas could be induced in the implantation cysts. The same procedure failed to yield such clear-cut results using other strains of mice. Our procedure for short term testing of substances for carcinogenic potential derived from these observations, is described below. It is essentially simple and we feel it is worth mentioning certain manipulations which permit a rapid turnover of material. Our experiments also confirm that " c " mice are the most satisfactory to use. MATERIAL AND METHODS Source of implant material BALB/c strain female mice were segregated into individual boxes when obviously pregnant, and when within 48 hours of term were killed by cervica

The Angular Power Spectrum of EDSGC Galaxies

We determine the angular power spectrum, C_l, of the Edinburgh/Durham Southern Galaxy Catalog (EDSGC) and use this statistic to constrain cosmological parameters. Our methods for determining C_l, and the parameters that affect it are based on those developed for the analysis of cosmic microwave background maps. We expect them to be useful for future surveys. Assuming flat cold dark matter models with a cosmological constant (constrained by COBE/DMR and local cluster abundances), and a scale--independent bias, b, we find good fits to the EDSGC angular power spectrum with 1.11 < b < 2.35 and 0.2 < Omega_m < 0.55 at 95% confidence. These results are not significantly affected by the ``integral constraint'' or extinction by interstellar dust, but may be by our assumption of Gaussianity.Comment: 11 pages, 9 figures, version to appear in Ap

Vegetative key to the alpine vascular plants of mount Kenya

Volume: 7

Temperature determination via STJ optical spectroscopy

ESA's Superconducting Tunnel Junction (STJ) optical photon-counting camera (S-Cam2) incorporates an array of pixels with intrinsic energy sensitivity. Using the spectral fitting technique common in X-ray astronomy, we fit black bodies to nine stellar spectra, ranging from cool flare stars to hot white dwarfs. The measured temperatures are consistent with literature values at the expected level of accuracy based on the predicted gain stability of the instrument. Having also demonstrated that systematic effects due to count rate are likely to be small, we then proceed to apply the temperature determination method to four cataclysmic variable (CV) binary systems. In three cases we measure the temperature of the accretion stream, while in the fourth we measure the temperature of the white dwarf. The results are discussed in the context of existing CV results. We conclude by outlining the prospects for future versions of S-Cam.Comment: 9 pages, 9 figures (11 files); uses aa.cls; accepted for publication in A&

Simulated Extragalactic Observations with a Cryogenic Imaging Spectrophotometer

In this paper we explore the application of cryogenic imaging spectrophotometers. Prototypes of this new class of detector, such as superconducting tunnel junctions (STJs) and transition edge sensors (TESs), currently deliver low resolution imaging spectrophotometry with high quantum efficiency (70-100%) and no read noise over a wide bandpass in the visible to near-infrared. In order to demonstrate their utility and the differences in observing strategy needed to maximize their scientific return, we present simulated observations of a deep extragalactic field. Using a simple analytic technique, we can estimate both the galaxy redshift and spectral type more accurately than is possible with current broadband techniques. From our simulated observations and a subsequent discussion of the expected migration path for this new technology, we illustrate the power and promise of these devices.Comment: 30 pages, 10 figures, accepted for publication in the Astronomical Journa