30 research outputs found
Demonstrator of Time Services based on European GNSS signals: the H2020 DEMETRA Project
During 2015-2016, a European Consortium of 15 partners from 8 different
countries, developed the DEMETRA (DEMonstrator of EGNSS services based
on Time Reference Architecture), a project funded by the European Union
in the frame of the Horizon 2020 program. This project aims at
developing and experimenting time dissemination services dedicated to
specific users like traffic control, energy distribution, finance,
telecommunication, and scientific institutions. Nine services have been
developed. These services provide time dissemination with accuracy
levels from millisecond to the sub-ns, and also additional services like
certification, calibration, or integrity. Five of these services are
based on the European GNSS.
After a development phase (see PTTI 2016 presentation) the full DEMETRA
system has been working during six months for demonstration. The paper
will report about the experimentation results, showing performances and
limits of the proposed time dissemination services, aiming to foster the
exploitation of the European GNSS for timing applications
Glycoprotein biosynthesis in isolated rat hepatocytes during pre- and postnatal development
Age-related changes of glycosylation pattern in isolated rat hepatocytes
The glycosylation pattern in isolated rat hepatocytes during pre- and post-natal development and senescence has been studied by following: the [14C]glucosamine and [3H]galactose incorporation into cellular glycoproteins and glycolipids and the activity of two microsomal enzymes, N-acetyl-glucosaminyl-1-P transferase and galactosyl transferase. The data show a lowered precursor incorporation into lipids and proteins in the fetus, newborn and old rats versus the adult. Only the galactosyl transferase activity is enhanced on the 19th and 22nd day of fetal life. The glucosamine and N-acetyl-glucosamine content in both soluble and protein bound fractions was increased, while the galactose content in lipids and proteins decreased in the fetal stage. The different sugar composition of the proteins, and the decreased glucosamine and galactose incorporation into the proteins, observed in the fetus, newborn and old rat, suggest a post-translational modification which may cause alterations in functions usually mediated by glycoprotein
Regulation of 3-hydroxy-3-methylglutaryl Coenzyme A reductase by mevalonate and cholesterol in isolated rat hepatocytes during perinatal development
Hormone responsiveness of plasma membrane-bound enzymes in normal and regenerating rat liver
The hormonal responsiveness of plasma membrane-bound enzymes (Na+-K+)-ATPase and adenylate cyclase has been investigated in normal and regenerting rat liver. (Na+-K+)-ATPase basal activity is not affected by surgery and only slightly affected by partial hepatectomy; its response to epinephrine and cyclic AMP is decreased only 15 h after hepatectomy. Adenylate cyclase activity of plasma membranes from untreated animals is stimulated by parathyroid hormone and thyroxine; partial hepatectomy increased basal activity as well as the stimulation exerted by the aforementioned hormones, when glucagon and epinephrine sensitivity is essentially unaltered. © 1975
Mechanism of rapid modulation of HMGCoA reductase in isolated hepatocytes during fetal and poerinatal life
Cholesterologenesis and related enzymes in isolated rat hepatocytes during pre- and postnatal life
Cholesterogenesis pathway during pre- and postnatal development was studied in isolated rat hepatocytes. No modified activity of cytosol acetoacetyl coenzyme A (CoA), thiolase, or 3-hydroxy-3-methylglutaryl CoA (HMGCoA) synthase was detectable at the different stages examined. Minimal levels of 1(14)C-acetate incorporation into cholesterol and HMGCoA reductase activity were present at 16 days of fetal development in newborn and suckling rats, whereas both parameters increased rapidly before birth. The pattern of NaF nonsuppressible reductase activity showed a different activation state of the enzyme, suggesting the appearance of a modulation state, probably related to the development of some short-term regulatory mechanisms