Showing papers on "Selenium published in 1970"

Nutrient composition of selected wheats and wheat products. VI. Distribution of manganese, copper, nickel, zinc, magnesium, lead, tin, cadmium, chromium, and selenium as determined by atomic absorption spectroscopy and colorimetry.

Abstract: Magnesium and eight trace mineral elements, manganese, copper, nickel, zinc, lead, tin, cadmium, and chromium, were determined by atomic absorption spectroscopy in 11 known wheats or wheat blends, 20 commercially prepared flours from these wheats, and 25 specially prepared products from the flours. The same minerals were determined in ten consumer products from ten different cities. There was significant variation among the five hard wheats in their content of nickel, zinc, lead, tin, cadmium, and chromium. Manganese, copper, zinc, cadmium, and chromium varied significantly in the four soft wheat samples, most of the variation being contributed by a single low mineral wheat. The concentration of manganese, copper, zinc, and magnesium were about the same or lower and nickel, tin, cadmium, and chromium higher in the cake and crackers than in the respective flour from which they were made. Although there were significant variations in the lead, cadmium, and chromium concentrations in most of the market samples of consumer products there was no discernible effect of geographic location on the general mineral content of these products. Whole-wheat consumer products contained greater concentrations of manganese, copper, zinc, magnesium, and chromium than did products made from white flour. The selenium content of amore » small group of wheat blends and products was determined by a colorimetric method. 8 references, 7 tables.« less

The uptake of applied selenium by agricultural plants. 2. The utilization of various selenium compounds.

Abstract: SummaryElemental selenium and a series of selenites and selenates were applied in pot and field experiments. With the elemental selenium a small increase in concentration in the plants was found in both kinds of experiments with red clover, lucerne, mustard, andsugar beet as test plants, but not with barley. In the second year an increase in the concentration in the plants was found in lucerne only (field experiment). In a pot experiment eight successive cuts of clover all had nearly the same content.All the selenites had the same effect on the concentration in the plants, and the concentration in the eight cuts of clover decreased with time at the same rate for all six selenites irrespective of solubility. The decrease was about a factor of six. In the field the effect of K2SeO3 in the second year was reduced by 50 to 80 per cent.Also the selenates gave the same concentration in plants independently of the solubility. But the concentration was 20–50 times that obtained with selenites, and the decrease in the effect with time was greater. In the eight clover cuts the effect of selenate decreased four times as much as the effect of selenite. In the field the effect of K2SeO4 decreased more from the first to the second year than the effect of BaSeO4.During a two years field experiment with mustard the total uptake as a percentage of the added selenium was 0.01% of Se°, 4% of K2SeO3 and 30% of K2SeO4 and BaSeO4. With lucerne, barley and sugar beet the uptake was one third of this or less.Determinations of water-extractable selenium in profiles from the field in the autumn showed no increase succeeding the addition of K2SeO4 in the spring while the addition of BaSeO4 increased the extractable amount in both autumns. Addition of five times more selenite increased the water-extractable as well as the total soil selenium in the upper 25 cm, and the increase in total Se was also present in the second autumn.

Analysis of arsenic and selenium in marine raw materials.

Abstract: The content of arsenic and selenium has been analysed in the following marine organisms: cod (Gadus morhua), herring (Clupea harengus), mackerel (Scomber scomber), Norway haddock (Sebastes marinus), lobster (Homarus vulgaris), mussel (Mytilus edulis), clam (Pecten maximus), oyster (Ostrea edulis), squid (Ommastrephes sagittatus) and whale (Balaenoptera physalus). The analyses were performed both on the raw material and in the water-soluble phase after the samples had been boiled (the N liquor). An enrichment of arsenic is observed in the N liquor, compared with the raw material. The results indicate that selenium is also enriched in the N liquor from fish, but not from the invertebrate animals analysed. The N liquor and the water-soluble phase of the enzyme-hydrolysed presscake (the water-insoluble phase after boiling) were fractionated by molecular gel nitration. Fractions from these elutions were analysed for arsenic and selenium. Selenium was present in the fractions with a molecular weight above about 5000. Arsenic was connected with the lower molecular weight fractions, and may be present as more arseno-organic compounds.

Concentrations of Trace Elements in Great Lakes Fishes

Abstract: The concentration of 15 trace elements was determined by activation analysis of samples of whole fish and fish livers from three of the Great Lakes: Michigan, Superior, and Erie. The average concentrations of 7 elements in 19 whole fish from 3 species were as follows: uranium, 3 ppb (parts per billion); thorium, 6 ppb; cobalt, 28 ppb; cadmium, 94 ppb; arsenic, 16 ppb; chromium, 1 ppm; and copper, 1.3 ppm. The average concentrations of 8 elements in 40 liver samples from 10 species of fish were as follows: uranium, −2 ppb; thorium, ≤ 2 ppb; cobalt, 40 ppb; copper, 9 ppm; zinc, 30 ppm; bromine, 0.4 ppm; arsenic, 30 ppb; and cadmium, 0.4 ppm. Other elements observed in most of the samples were: antimony, 5–100 ppb; gold, 2–5 ppb; lanthanum, 1–20 ppb; rhenium, 0.5–5 ppb; rubidium, 0.06–4 ppm; and selenium, 0.1–2 ppb.Trace element concentrations varied with species and lake. Uranium and thorium varied with species, but not for the same species from different lakes. The levels of copper, cobalt, zinc, and bromi...

Blood selenium in Thai children with protein-calorie malnutrition.

Abstract: SummaryProtein-calorie malnutrition in Thai infants and young children is associated with significant reduction in plasma selenium without change in red cell selenium. Plasma selenium was restored to normal levels by treating these children with therapeutic diets containing protein, vitamins, and minerals but no added selenium.

Interactions of methionine, vitamin E, and antioxidants in selenium toxicity in the rat.

Abstract: Female Wistar albino rats were fed a low vitamin E diet based on peanut meal and containing 10 ppm selenium as Na2SeO4. Supplementation of the diet with either 0.5% DL-methionine (Met) or 0.05% rfi-a-tocopheryl acetate (E) alone gave little protection against the liver damage due to selenium. However, a combination of 0.5% Met plus 0.01 to 0.05% E gave increasingly better protection depending on the level of E added. Combinations of 0.5% Met plus 0.05% N,N'-diphenyl-p-phenylenedi- amine, l,2-dihydro-6-ethoxy-2,2,4-trimethylquinoline, or butylated hydroxytoluene were also effective against liver damage, whereas supplements of 0.5% Met plus 0.1% di- sodium ethylenediaminetetraacetate, 0.25% mA©thylA¨ne blue, or 0.5% ascorbic acid gave little or variable protection against selenium. Replacement of the 0.5% Met with equi- molar amounts of cysteine, betaine, or cysteine plus betaine gave variable results. Addition of 0.39% guanidoacetic acid to a diet supplemented with 0.5% Met and 0.05% E appeared to inhibit the protective effect of the Met-E combination. Selenium levels in the livers and kidneys of rats fed supplements which protected against sele nium poisoning were lower than those of the animals fed the unsupplemented selenifer- ous peanut meal diet. It is suggested that vitamin E and the fat-soluble antioxidants make the methyl group of methionine more available for selenium detoxification.

The investigation of atomic motions in crystalline, amorphous and liquid selenium, and in crystalline and liquid tellurium by neutron spectroscopy

Abstract: The energy spectra of monochromatic neutrons scattered on selenium and telllurium have been investigated by means of a rotating crystal spectrometer. In polycrystalline selenium the highest spectral line can be identified as an intrachain bond stretching mode. Transforming selenium from its crystalline to its amorphous and liquid state, the shift of the line energy is only a few percent. The other lines in the spectra (from bond shearing and torsional modes of the chains) are influenced more strongly. For tellurium, on the other hand, the spectral lines of the solid disappear completely in the liquid phase. The experimental results are compared with the results of optical spectroscopy. Furthermore, the diffusive motion of the atoms has been studied by quasi-elastic neutron scattering for liquid selenium containing various admixtures of iodine (0–6 %), which change the average chain length of the polymeric melt, and for liquid tellurium. For Se, one obtains an effective diffusion constant D which describes the motion of small chain segments over atomistic distances. D is of the order of 10–5 cm2/s. Its activation energy was about 5 Kcal/mol.

Copper and selenium interaction in sheep.

Abstract: Extract Both selenium and copper are required elements in the diet of animals. Deficiency of either of them can lead to the development of a number of distinct disease entities which can be prevented by adequate supplementation of the diet.

The effect of selenium on infertility in ewes grazing improved pastures

Abstract: Trials conducted in South Australia, in an area where pasture improvement by means of the introduction of subterranean clovers has been practised for 10-15 years, have shown a significant improvement in fertility, in ewes treated with selenium. Analysis of all pastures grazed, and of whole blood of stock grazing them, indicated that the selenium status of the feed and of the animals was low. Phyto-oestrogen assays showed the presence of the isoflavones formononetin, genistein, and biochanin A, in the subterranean clover, which was mainly the cultivar Yarloop (Trifolium subterraneum L. var. Yarloop). Administration of selenium four to eight weeks before mating, given either as an oral dose of sodium selenite, or supplied in the form of an intraruminal selenium pellet containing elemental selenium and iron, led to an improvement in fertility; in some cases from 49 to 76 per cent. Also, lamb mortality was reduced by selenium administration to the ewes. There were differences due to selenium administration (P<0.001). Ewe fertility differed between pastures designated 'oestrogenic' and 'non-oestrogenic' (P<0.05). But no interaction between selenium and the presence of phyto-oestrogens could be shown by these experiments. The results are discussed in relation to the problem of infertility associated with the grazing of improved pastures

ESR investigations on liquid sulphur and selenium

Abstract: Peak 1 was trans,syn-A2-octalol-l (40): ir (CCl,) 3633 (s , free OH) and 3500 cm-’ (m, b , bonded OH); nmr S 5.88 (m, 2, CH=CH), 3.88 (broad singlet, 1, CHOH), 1.33 (s, 1, OH), and 0.50-2.40 (broad band, 13, all other protons). It was hydrogenated over Adams catalyst in methanol to trans,syn-1decalol (38) whose ir was identical with that of authentic 38.21 Anal. Calcd for CloHleO (152.23): C, 78.89; H, 10.59. Found: C, 78.62; H, 10.49. Peak 2 was Irans,anti-A2-octalol-l (41): ir (CCL) 3625 and 3650 (s, free OH), and 3500 cm-1 (s, b, bonded OH); nmr 8 5.60 (m, 2, CH=CH), 3.80 (broad singlet, 1, CHOH), 1.67 (9, 1, OH), and 0.50-2.40 (broad band, 13, all other protons). Its ir absorption in dilute carbon tetrachloride solution in the intermolecular 0-H stretching region was more intense than in the corresponding spectrum of 40. I t was hydrogenated over Adams catalyst in methanol to trans,anti-1-decalol (39) whose ir was identical with that of authentic 39.21 Jones oxidation of fraction 2 produced the enone 42 which was collected by preparative glpc (column A) and subsequently reduced by lithium aluminum hydride to a mixture which contained ca. 95Yo 41. Anal. Calcd for CloHlgO (152.23): C, 78.89; H, 10.59. Found: C , 78.61; H, 10.39. Peak 3 was not identified.

Mechanism of selenium dioxide oxidation of olefins

Abstract: Peak 1 was trans,syn-A2-octalol-l (40): ir (CCl,) 3633 (s , free OH) and 3500 cm-’ (m, b , bonded OH); nmr S 5.88 (m, 2, CH=CH), 3.88 (broad singlet, 1, CHOH), 1.33 (s, 1, OH), and 0.50-2.40 (broad band, 13, all other protons). It was hydrogenated over Adams catalyst in methanol to trans,syn-1decalol (38) whose ir was identical with that of authentic 38.21 Anal. Calcd for CloHleO (152.23): C, 78.89; H, 10.59. Found: C, 78.62; H, 10.49. Peak 2 was Irans,anti-A2-octalol-l (41): ir (CCL) 3625 and 3650 (s, free OH), and 3500 cm-1 (s, b, bonded OH); nmr 8 5.60 (m, 2, CH=CH), 3.80 (broad singlet, 1, CHOH), 1.67 (9, 1, OH), and 0.50-2.40 (broad band, 13, all other protons). Its ir absorption in dilute carbon tetrachloride solution in the intermolecular 0-H stretching region was more intense than in the corresponding spectrum of 40. I t was hydrogenated over Adams catalyst in methanol to trans,anti-1-decalol (39) whose ir was identical with that of authentic 39.21 Jones oxidation of fraction 2 produced the enone 42 which was collected by preparative glpc (column A) and subsequently reduced by lithium aluminum hydride to a mixture which contained ca. 95Yo 41. Anal. Calcd for CloHlgO (152.23): C, 78.89; H, 10.59. Found: C , 78.61; H, 10.39. Peak 3 was not identified.