Broad applications of diffusion bonding

Solid state joining of materials by diffusion bondin

Activation of murine leukaemia virus under different physiological conditions.

The leukaemic lesions in intact and ovariectomized mice of strain ICRC, induced with 20-methylcholanthrene (20-MCA) in combination with or without hormones were investigated for the presence of mouse leukaemia virus (MuLV) by (i) bioassays and (ii) electron microscopy. The different experimental groups treated with 20-MCA were (i) intact females, (ii) ovariectomized females, (iii) ovariectomized females with pituitary graft, (iv) ovariectomized females with 10 mug oestradiol/day for 30 days and (v) ovariectomized females with 1 mug oestradiol together with 1 mg progesteron/day for 30 days. It was possible to transmit nearly all these experimentally induced leukaemias to syngeneic mice through acellular extracts, compared with very poor transmissibility of spontaneous leukaemias in the ICRC strain, indicating functional activation of viral agents on combined treatment with carcinogen and hormones. Potency of the acellular leukaemic extract from the mice of group (ii) without the ovarian hormones was much weaker than that from mice of the other experimental groups. The leukaemogenic activity of MuLV was enhanced on serial transmission in syngeneic hosts. Leukaemic lesions of ovariectomized mice treated with 20-MCA and oestradiol were also transmissible to the sucklings of allogeneic mice of strain C3H-MTV, C57-BL and Dba-MTV. The cell-free supernatant medium of the cultures of these leukaemic lesions induced leukaemias on back inoculation into syngeneic mice. Electron microscopic studies of lesions induced with carcinogen and oestradiol consistently showed abundant intracytoplasmic type A particles. Numerous intracytoplasmic type A particles as well as some type B particles were found in the leukaemic tissues of ovariectomized females treated with MCA and oestradiol combined with progesterone. Type C particles, characteristic of MuLV were seen in the leukaemic tissues of all other experimental groups. These findings indicate a significant influence of the physiological condition of the host, particularly the hormonal make up, on expression and activity of specific viral agents

Extragalactic radio sources with sharply inverted spectrum at metre wavelengths

We present the first results of a systematic search for the rare extragalactic radio sources showing an inverted (integrated) spectrum, with spectral index $\alpha \ge +2.0$, a previously unexplored spectral domain. The search is expected to yield strong candidates for $\alpha \ge +2.5$, for which the standard synchrotron self-absorption (characterized by a single power-law energy distribution of relativistic electron population) would not be a plausible explanation, even in an ideal case of a perfectly homogeneous source of incoherent synchrotron radiation. Such sharply inverted spectra, if found, would require alternative explanations, e.g., free-free absorption, or non-standard energy distribution of relativistic electrons which differs from a power-law (e.g., Maxwellian). The search was carried out by comparing two sensitive low-frequency radio surveys made with sub-arcminute resolution, namely, the WISH survey at 352 MHz and TGSS/DR5 at 150 MHz. The overlap region between these two surveys contains 7056 WISH sources classified as `single' and brighter than 100 mJy at 352 MHz. We focus here on the seven of these sources for which we find $\alpha > +2.0$. Two of these are undetected at 150 MHz and are particularly good candidates for $\alpha > +2.5$. Five of the seven sources exhibit a `Gigahertz-Peaked-Spectrum' (GPS).Comment: 8 pages, 2 figures, accepted for publication in MNRA

Circulating levels of prolactin in human breast cancer.

Serum prolactin concentrations were measured by radioimmunoassays in 98 patients with established carcinoma of breast, 12 patients with cystic mastitis and 10 patients with gynaecomastia and compared with that of age matched normal control women. The serum prolactin levels in the patients with breast cancer, gynaecomastia or cystic mastitis were observed to be similar to that in normal women. It was interesting to note that the levels of prolactin in the luteal phase of the cycle were higher than that in the early follicular phase in normal women

Aerobic Exercise Training Affects Exercise Pressor Reflex in Older Adults

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On the degree of approximation by positive linear operators using the b-summability method

The aim of this paper is to sharpen the results of censor [3] and Mahapatra [7] given on the degree approximation by positive linear operators