(n.) An instrument for showing the operation of the causes which produce the succession of day and night, and the changes of the seasons.
Example Sentences:
Tellurium
Definition:
(n.) A rare nonmetallic element, analogous to sulphur and selenium, occasionally found native as a substance of a silver-white metallic luster, but usually combined with metals, as with gold and silver in the mineral sylvanite, with mercury in Coloradoite, etc. Symbol Te. Atomic weight 125.2.
Example Sentences:
(1) Beryllium, cadmium, and tellurium assay data are reported for the fresh tissues of albino rats exposed to inorganic chemicals by oral or intraperitoneal routes.
(2) One of the earliest ultrastructural abnormalities in tellurium neuropathy is an increased number of cytoplasmic lipid droplets in myelinating Schwann cells.
(3) Exposure to tellurium resulted in an early marked decrease of approximately 50% in overall incorporation of [14C]acetate into lipids, with a preferential depression in synthesis of cerebrosides, cholesterol, and ethanolamine plasmalogens (components enriched in myelin).
(4) Ter plasmids from tellurium-resistant bacteria that were isolated from sewage and industrial wastes also mediated phage inhibition.
(5) Plasmids determining resistance to arsenic, mercury, silver, and tellurium compounds in Escherichia coli and Pseudomonas aeruginosa were tested for resistance to 40 other metal compounds.
(6) These data indicate that the tellurium-induced lipid droplets in Schwann cells are derived from newly synthesized lipid rather than from the early breakdown and internalization of myelin lipids.
(7) Tellurium-induced alterations in the metabolic capacity of Schwann cells were examined by measuring the synthesis of myelin lipids in vitro in isolated sciatic nerve segments.
(8) At the onset of acute demyelination induced by tellurium (Te) poisoning, macrophages infiltrated the endoneurium and then began to express cytoplasmic immunoreactivity for apolipoprotein E (apo E).
(9) Tellurium concentrations were measured in urine samples by means of graphite furnace atomic absorption spectroscopy (GFAAS) after wet ashing and a preconcentration of tellurium by solvent extraction with isobutyl methyl ketone (IBMK).
(10) The elements studied were arsenic, tellurium, tin, and lead.
(11) Membrane-delimited vacuoles, lipid droplets and cytoplasmic excrescences appeared in myelinating Schwann cells at 24 hr; demyelinating axons appeared at 48 hr of tellurium exposure.
(12) Reliable isotope ratios could be determined with sample fractions containing 1 ng of tellurium or even less.
(13) When analyzed on a 'per nerve' basis, steady-state mRNA levels for these two proteins were actually increased about 2-fold by 9 days after beginning tellurium exposure.
(14) These results imply that both selenium and tellurium can be incorporated into the protein molecule as the respective labile components.
(15) Message levels increased during the subsequent period of remyelination and reached near-normal levels 30 days after beginning tellurium exposure.
(16) A stable population of intraspinal Schwann cells, which developed following early postnatal irradiation of the spinal cord, was challenged by the addition of tellurium (Te) to the diet beginning at 30 days of age.
(17) Exposure of developing rats to tellurium results in a highly synchronous segmental demyelination of peripheral nerves with sparing of axons; this demyelination is followed closely by a period of rapid remyelination.
(18) In the prelabeled nerves, myelin became heavily labeled, but the tellurium-induced cytoplasmic lipid droplets were rarely labeled.
(19) The reaction can, however, be terminated, even in the presence of tellurite, by addition of N-ethylmaleimide, presumably due to the blockage of thiols or thiol-analogous tellurium compounds.
(20) The 123Xe yields from natural tellurium are too low for routine production.