655 research outputs found
Autonomy and dependence of preneoplastic mammary nodules in mice.
HYPERPLASTIC alveolar nodules have been shown to represent the preneo-plastic state in mouse mammary tumour development (Bern and Nandi, 1961). With little or no mammary gland substrate (due to the inherited hormonal pattern), neither nodules nor tumours arise unless an appropriate level of activity is artificially induced in the tissue. LAF1 mice (generally considered to be free of the mammary tumour agent), had previously been shown to be refractory to methylcholanthrene mammary carcinogenesis (Haran-Ghera, 1961). This failure could, however, be overcome by stimulating the mammary glands with increased prolactin secretion which in-duced hyperplastic nodules in this tissue. Simultaneous action of the carcinogen and mammary gland stimulation were foumd to induce preneoplastic lesions that eventually developed in intact LAF1 mice into autonomous mammary tumours (Haran-Ghera, 1963). The present experiments were set up on the basis of these findings, in order to determine the hormonal requirements for further neoplastic transformatio
The mechanism of radiation action in leukaemogenesis. The role of radiation in leukaemia development.
RADIATION-INDUCED tumours in low leukaemic strains are actually produce
Congruence schemes
A new category of algebro-geometric objects is defined. This construction is
a vast generalization of existing F1-theories, as it contains the the theory of
monoid schemes on the one hand and classical algebraic theory, e.g.
Grothendieck schemes, on the the other. It also gives a handy description of
Berkovich subdomains and thus contains Berkovich's approach to abstract
skeletons. Further it complements the theory of monoid schemes in view of
number theoretic applications as congruence schemes encode number theoretical
information as opposed to combinatorial data which are seen by monoid schemes
The mechanism of radiation action in leukaemogenesis. Isolation of a leukaemogenic filtrable agent from tissues of irradiated and normal C57BL mice.
IRRADIATION of C57B1 mice induced a high incidence of lymphatic leukaemia, while being refractory to the spontaneous development of the disease. Several investigators have isolated a leukaemogenic agent from these radiation-induced tumours, which produces lymphoid leukaemia when injected into isologous newborn or young adult non-irradiated mice (Lieberman and Kaplan, 1959; Latarjet and Duplan, 1962; Laznicka and Smetanova, 1963; Ilbery and Winn, 1964). It has been assumed that the leukaemogenic agent is present during post-natal life in non-irradiated C57B1 mice, and that ionizing irradiation causes the release of a leukaemogenic agent, in addition to thymus and bone marrow injury, which are essential factors in radiation leukaemogenesis (Kaplan, 1964). Experimental support for this hypothesis was provided by demonstrating the presence of a leukaemogenic agent, for a limited period after completion of the irradiation treatment, in centrifugates prepared from pooled, irradiated, non-]eukaemic thymus and bone marrow (Haran-Ghera, 1966). The aim of the present studies was to isolate a leukaemogenic filtrate fro
Seismic Foundation Retrofit of West Stands of Michie Stadium
The Michie Stadium is located at the U.S. Military Academy at West Point, New York. The West Stands of the stadium, consisting of upper and lower tier seating and other facilities, are supported on columns which are founded on shallow footings resting mainly on shallow bedrock. A structural seismic assessment of the West Stands indicated that uplift of the foundations would occur during a seismic event thereby causing significant distress to the superstructure. In order to prevent the uplift of the foundations and to provide base fixity, it was proposed to install rock anchors through the foundation. A supplementary subsurface investigation program consisting of borings and test pits was carried out to estimate the bedrock elevations and characterize the bedrock. In addition, full-scale anchor pull-out tests were performed to evaluate the bond-strength between the anchorage and rock interface. This paper will present the design of the anchorage system including the concrete reaction ring installed around the base of the column and the rock anchor system. The paper also includes the results of the full-scale anchor tests and modifications that had to be made to the design during construction due to unforeseen foundation conditions
Magnetism of Superconducting UPt3
The phase diagram of superconducting in pressure-temperature
plane, together with the neutron scattering data is studied within a two
component superconducting order parameter scenario. In order to give a
qualitative explanation to the experimental data a set of two linearly
independent antiferromagnetic moments which emerge appropriately at the
temperature \mbox{} and \mbox{} and
couple to superconductivity is proposed. Several constraints on the fourth
order coefficients in the Ginzburg-Landau free energy are obtained.Comment: 17 pages, figures available on request to
[email protected]
Permanence criteria for semi-free profinite groups
We introduce the condition of a profinite group being semi-free, which is
more general than being free and more restrictive than being quasi-free. In
particular, every projective semi-free profinite group is free. We prove that
the usual permanence properties of free groups carry over to semi-free groups.
Using this, we conclude that if k is a separably closed field, then many field
extensions of k((x,y)) have free absolute Galois groups.Comment: 24 page
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