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We successfully design and experimentally demonstrate a challenging optical wireless communication (OWC) link connecting two units placed on the roof of a satellite, thus removing the electrical cable. The system design accounts for the impact of the strong sunlight and the realistic misalignment. First, we precisely quantify the maximum sunlight intensity at the OWC receiver in the worst case, i.e., when the sun is aligned with the optical axis of the link. We then experimentally realize a MIL-STD-1553 OWC system by commercially available components, in a directed line-of-sight configuration: we set a nonnegligible value of beam divergence (4°) to provide both high-signal intensity at the receiver and the required tolerance to misalignment. The link is experimentally analyzed in the lab, first under normal illumination and then emulating the intensity of the (filtered) sunlight. In the experiments, the quality of the transmitted MIL-STD-1553 signal is successfully assessed by means of test modules for industry-level qualification. Most importantly, the link margins are so high that the system effectively works even under direct sunlight. Finally, the measured tolerance to misalignment proves that our system is robust to misplacement of the transceivers (around ±15 mm), e.g., due to vibrations.

Estrogen controls key cellular functions of responsive cells including the ability to survive, replicate, communicate and adapt to the extracellular milieu. Changes in the expression of 8400 genes were monitored here by cDNA microarray analysis during the first 32 h of human breast cancer (BC) ZR-75.1 cell stimulation with a mitogenic dose of 17beta-estradiol, a timing which corresponds to completion of a full mitotic cycle in hormone-stimulated cells. Hierarchical clustering of 344 genes whose expression either increases or decreases significantly in response to estrogen reveals that the gene expression program activated by the hormone in these cells shows 8 main patterns of gene activation/inhibition. This newly identified estrogen-responsive transcriptome represents more than a simple cell cycle response, as only a few affected genes belong to the transcriptional program of the cell division cycle of eukaryotes, or showed a similar expression profile in other mitogen-stimulated human cells. Indeed, based on the functions assigned to the products of the genes they control, estrogen appears to affect several key features of BC cells, including their metabolic status, proliferation, survival, differentiation and resistance to stress and chemotherapy, as well as RNA and protein synthesis, maturation and turn-over rates. Interestingly, the estrogen-responsive transcriptome does not appear randomly interspersed in the genome. In chromosome 17, for example, a site particularly rich in genes activated by the hormone, physical association of co-regulated genes in clusters is evident in several instances, suggesting the likely existence of estrogen-responsive domains in the human genome.

Inhibitors of 3-hydroxy-3-methylglutaryl (HMG)-CoA reductase, such as Simvastatin and Lovastatin, reduce the rate of DNA synthesis and proliferation of a wide variety of cell types in vitro, by inducing a cell cycle arrest in G1. In estrogen-free medium, DNA synthesis is reduced by more that 90% following exposure of normal and transformed human breast epithelial cells to 20μM Simvastatin or Lovastatin for 24 to 42hrs. We show here that stimulation of estrogen responsive MCF-7 cells with nanomolar concentrations of 17β-estradiol (E2) prevents inhibition of DNA synthesis by these compounds. The effect of the hormone is antagonized by both steroidal and non steroidal antiestrogens, and it is not detectable in estrogen receptor-negative MCF-10a cells. Cell cycle analysis demonstrates that HMG-CoA reductase inhibitors are unable to induce G1arrest of MCF-7 cells in the presence of E2.

1. At the example of the production of liver cancer in rats by feeding with 4-dimethyl-aminoazobenzene the problem is examined, whether the metabolism in the liver gradually turns into the cancer-metabolism or suddenly only then, when the carcinogenic degeneration is complete.

RECENT research (see refs. 1–3) has shown that 17β-oestradiol is specifically taken up and retained, without detectable chemical transformation, by uterus, vagina, adenohypophysis, mammary gland4and hypothalamus5. In contrast, other organs rapidly release or transform it. In target tissues most of the hormone is found in the nuclear fraction—up to 80 per cent, depending on the homogenization conditions—and the rest is mostly in the 105,000g supernatant6–10. Toft and Gorsky11,12found that the hormone in the supernatant is bound in larger part to a macromolecule (9.5S) which, at least in part, consists of protein and has the properties of a specific receptor for oestrogens, that is, it shows a high affinity and specificity for oestrogenic molecules.

IT was shown1that strips of immature calf uterus incubated in vitro in the presence of 10−9M 3H-oestradiol-17β concentrate the hormone 400 per cent or more; about 80 per cent of the radioactivity in the tissue is found associated strongly but non-covalently with the nuclear fraction and consists of intact 17β-oestradiol; treatment of the nuclear fraction with 0.4 M KCl at pH 8.5, as already applied by us to rat2, solubilizes an oestradiol-macromolecule complex which sediments at about 5S; the macromolecule is protein, or at least the moiety binding the hormone is protein. A similar 5S oestrophilic component from calf uterus was obtained by Jungblut et al.3. Recent studies4–6suggest that the 5S macromolecule originates from the 8–10S macromolecular component which binds 17β-oestradiol and is found in the high speed supernatant of uterus.

WHEN 17β-oestradiol and other oestrogens enter a target cell they are bound by highly specific oestrophilic proteins in a strong but non-covalent manner (Kass≃1.3 × 109–1.5 × 109M−1for 17β-oestradiol)1. These oestrogen receptors are found in both nuclear and cytoplasmic fractions of uterus and other target organs to this hormone1–11. We now report (1) that iodination of calf uterus oestrogen receptors in alkaline media at lowered temperature destroys their ability to bind 17β-oestradiol; (2) that this effect cannot be ascribed to oxidation of SH groups; and (3) that iodination is ineffective when the binding site is interacting with the hormone, and is thus protected from a direct effect.