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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 84 (1998), S. 634-640 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A new physics based model is developed for the small signal and large signal high current response of p-i-n photodetectors. The numerical treatment is not constrained by the numerical stability requirements of conventional treatments of the time-dependent drift-diffusion equations. The results confirm the finding of other authors in predicting the formation of an extended low field region at high currents, with consequent collapse of the frequency response. Comparison with available experimental data for GaAs based photodiodes suggests that 2D effects are important in the high current limit, but can be allowed for within the 1D model by reducing the calculated particle velocity in the low field region. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 75 (1994), S. 320-324 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The low temperature current-voltage characteristics of a strongly coupled, short-period GaAs/Al0.33Ga0.67As superlattice structure have been studied with applied magnetic fields both parallel and perpendicular to the current flow. The complex dependence of the current-voltage characteristics on magnetic field perpendicular to the current flow is consistent with a simple model based on Bloch transport via the lowest miniband. From fits to the data the scattering time and mobility have been estimated as 0.15 ps and 4100 cm2/V s, respectively. Further evidence of negative-differential velocity associated with miniband transport comes from the observation of an extended negative-differential resistance region at room temperature in a structure with 50 superlattice repeats.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 184 (1959), S. 897-898 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] I recently needed to design safety studs which would fracture at a load of 29,300 lb. with a maximum coefficient of variation of 1-3 per cent. The studs were 7 in. long and 1J in. in diameter with a circumferential groove of semi-circular section turned on it with a parting tool. It was found that ...
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 261 (1976), S. 66-66 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] AVT was conjugated to bovine serum albumin, and anti-serum to the complex was prepared in adult male guinea pigs. The antiserum was absorbed with 1 mg of bovine serum albumin per ml of undiluted serum before use. Pineal glands and hypothalami from ten adult male rats were fixed in Bouin's solution ...
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1434-0879
    Keywords: Receptors ; Oestradiol ; Dihydrotestosterone ; Urinary system ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary By light microscopic atuoradiography, the kidneys, ureters and urinary bladder of male and female baboons were examined in an effort to define which cells in these three organs were targets for oestradiol (E2) and dihydrotestosterone (DHT). In the parenchyma of the kidney, there was no specific uptake of either 3H-E2 or 3H-DHT, whereas the cortical and medullary connective tissue cells sequestered only 3H-E2. The latter hormone was also found in cells comprising the tunica intima and tunica media of the renal, interlobar and arcuate arteries. The two radiolabelled steroids were concentrated in connective tissue cells of the lamina propria of the ureter and bladder and in the tissue adjacent to smooth muscle fasciculi. Only 3H-DHT was retained by the smooth muscle in these two organs. These observations indicate that specific steroid binding sites are present in the urinary system of the baboon. Their role in the physiology of the kidney, ureter and urinary bladder remains at this point unclear.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 37 (1981), S. 1035-1036 
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Adult female armadillos were injected with tritiated estradiol. The pituitary gland was removed and processed for autoradiography. Nuclear uptake and retention of the steroid was found in 28.8% of the cells in the pars distalis and 3.7% of the pituicytes.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Histochemistry and cell biology 76 (1982), S. 567-575 
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The relationship between unbound and bound proteins prepared during labelling with colloidal gold (Au) was investigated. For this aim, labelled 125I-bovine serum albumin and 125I-rabbit immunoglobulin were employed. The procedures associated with the washing of the Au labelled proteins (i.e. albumin) had a marked influence on the dissociation of the bound ligand. This was most evident when the concentration of albumin that was used for labelling was too high (0.1 or 1.0 mg/ml Au sol). We suggest that purification of labelled proteins be conducted shortly before use so as to avoid a significant amount of dissociation during the time when the solution is coming to equilibrium.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-0878
    Keywords: Androgen ; Estrogen ; Gonadotrophs ; Lactotrophs ; Autoradiography ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Castrated adult male and female and androgenized female rats (AS rats) were injected i.v. with 3H-estradiol (E2). Nuclear uptake and retention of the 3H-steroid was examined in pituitary luteinizing hormone (LH) and prolactin (PRL) cells by the combined techniques of autoradiography and immunocytochemistry. About 80% of PRL cells were found to concentrate the radioactive steroid compound in all experimental groups, while 89%, 82% and 68% of LH cells were found to be labeled in AS rats, normal female and male rats, respectively. This suggests that there are subpopulations of LH or PRL cells that contain no or, if any, small numbers of E2 receptor. Statistical analysis revealed that PRL cells take up more radioactivity than LH cells in male rats, while there is no significant difference between female and AS rats. Variations in E2 uptake (coefficient of variation) was higher in LH cells than in PRL cells in male rats and in AS rats. In females, on the contrary, coefficient of variation was larger in PRL cells. Thus the characteristics of nuclear uptake and retention of estradiol in LH and PRL cells appear to be modulated in part by neonatal androgen since the pattern found in AS rats is different than that found in normal male and female rats.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 206 (1980), S. 35-40 
    ISSN: 1432-0878
    Keywords: Androgen receptors ; Pars nervosa ; Pars intermedia ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Castrated adult male hamsters and castrated adult female rats were injected with either 0.2 μg (hamsters) or 0.5 μg (rats) of 3H-dihydrotestosterone (107 Ci/mmole)/100 grams body weight and killed 11/2 h later. The pituitary glands were removed and processed for both autoradiography and immunocytochemistry (hamster) or only autoradiography (rats). Localization of the androgen was found in 10–15% of the cells of the pars distalis in both species. Only cells that stained for luteinizing hormone (LH) in the hamster's pars distalis concentrated the androgen. Also cells in both the pars intermedia and pars nervosa (1–5%) concentrated the androgen in both species. Although the number of cells that concentrated the androgen in the pars intermedia and pars nervosa was small, this finding may be related to recent physiologic data that suggest that the gonadal steroids may play a role in regulating water retention and natriuresis.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1432-0878
    Keywords: Cyproterone acetate ; Adenohypophysis ; Rhesus monkey ; Prolactin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Adult female rhesus monkeys were given cyproterone acetate orally in doses of 0.04, 0.4, 4 and 40mg per kg per day for 12 weeks. Its effects were assessed on serum prolactin (PRL) concentration, the morphology of the PRL cells, and the development of the mammary glands. Serum PRL was relatively unchanged in the control animals from the fourth through the twelfth weeks of the study. In contrast, PRL was significantly elevated in each group of drug-treated animals during the same time periods. There was no development of the mammary glands nor was there any evidence of milk secretion in the control animals; however, in the monkeys given cyproterone acetate the mammary glands had extensive lobuloalveolar growth and milk-like secretion that could be expressed as early as the fourth or fifth week of the study. By immunocytochemistry and differential light microscopic staining techniques, the PRL cells in the pituitary glands of the experimental animals were found to be more numerous and much larger than those present in the controls. They displayed a well developed Golgi complex and had an abundance of cytoplasmic RNA. These data suggest that PRL secretion is markedly enhanced by cyproterone acetate.
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