Trace elements boron

There are also the trace elements boron, copper, iron, manganese, zinc, molybdenum, and occasionally chlorine, which are important for some plant... 

Vasil eva, I. M., and Startseva, A. V. (1959). Effect of the trace elements boron, molybdenum, copper and zinc on the water conditions of red clover leaves (in Russian). Izv. Kazan. Fil. Akad. Nauk Ser. Biol. Nauk 7 39-47. 

Trace elements boron, Mn, Ho and Cu increased AA content in potato leaves These elements also increased the formation of chlorophyll and carotene in the leaves especially at the beginning of flowering The yield and starch contents also increased The beneficial effect of boron, Mn, and Cu on AA, and some physiological and biochemical processes of potato plants was reported by Gedz (1965) ... 

Among essential trace elements, boron is unusual in that the toxicity problems it produces are normally not persistent, because of the high mobility of this element combined as borate. On the other hand, this very property can produce phytotoxic problems which are very acute. 

Lower Oxides. A number of hard, refractory suboxides have been prepared either as by-products of elemental boron production (1) or by the reaction of boron and boric acid at high temperatures and pressures (39). It appears that the various oxides represented as B O, B O, B22O2, and B23O2 may all be the same material ia varying degrees of purity. A representative crystalline substance was determined to be rhombohedral boron suboxide, B12O2, usually mixed with traces of boron or B2O3 (39). A study has been made of the mechanical properties of this material, which exhibits a hardness... 

The Fermentation Process The process by which this antifungal substance is produced is an aerobic fermentation of an aquaous nutrient medium inoculated with a pimaricin-producing strain of Streptomycesgihrosporeus. The nutrient medium contains an assimilable source of carbon such as starch, molasses, or glycerol, an assimilable source of nitrogen such as corn steep liquor and Inorganic cations such as potassium, sodium or calcium, and anions such as sulfate, phosphate or chloride. Trace elements such as boron, molybdenum or copper are supplied as needed in the form of impurities by the other constituents of the medium. 

The sotrace elements, such as boron, cobalt, iron,copper, zinc, manganese, chromium, molybdenum and still others may also be used to advantage. Generally, these trace elements occur in sufficient quantities in the carbonaceous and nitrogenous constituents of the medium, particularly if derived from natural sources, or in the tap water, and the addition of further quantities of these trace elements may consequently be unnecessary. 

Silicon carbide, high boron borosilicate glass, trace elements in glass... 

Soil pH is easily tested for and determines the availability of nutrients and the success of white clover. Very acid soils (below pH 5.0) will cause a deficiency of the trace elements iron, boron, copper and molybdenum and conversely will cause injury to plant growth by increasing the availability of aluminium and manganese to toxic levels. Over-liming, on the other hand, which can raise the pH above 6.5, will reduce the availability of certain essential elements such as phosphorus, manganese and boron. 

The boron nitride obtained in this study was characterized by infrared spectroscopy, powder x-ray diffractometry and transmission electron microscopy. Trace elemental analyses were also performed by energy dispersive x-ray analysis and carbon arc emission spectroscopy. Representative spectra are displayed in Figures 2-4. 

Evolution did not use this element, only in certain plants is it important as a trace element. The element became well-known because of heat-resistant borosilicate glasses. Boranes are chemically interesting as B-H bonds react very specifically. Perborates are used in laundry detergents (Persil). The hardness of cubic boron nitride approaches that of diamond. Amorphous (brown) boron burns very quickly and gives off much heat and is therefore used in solid-propellant rockets and in igniters in airbags. 

Boron is an essential trace element for plants, and may well turn out to be essential for mammals as well. The boron-containing polyether-macrolide antibiotic, boromycin, was isolated as a potent anti-HIV agent. 

Boron deficiency on sweet corn overliming can disrupt the uptake by plants of this trace element... 

The historic use of trace-element geochemistry around the McArthur River Uranium Deposit has primarily focussed on a limited suite of elements, including uranium, lead, nickel, copper, and boron. At McArthur River, uranium is distributed around the main deposit to significant distances (100 s of meters) in the overlying Athabasca Group (McGill et al. 1993), yet variations in the uranium content of this halo is typically restricted to 1-3 parts per million with little spatial variation, restricting one s ability to vector... 

References to sample contaimination in the literature are numerous. Abercrombie, ef. oJ.(54) have noted that the information obtainable from ICP emission analysis warrants additional care because of the increased number of elements monitored. For example, if one were looking for boron and sodium, the use of glassware should be avoided. Certain digestion vessels that are presumed to be cleaned may not be acceptable. Polyethylene bottles (acid-soaked), for example, have been shown to continue releasing zinc from the matrix for as long as seven days(92). A number of trace elements may be leached from commercial disposable test tubes. Some of the more important contaminants include Ba, Sr, Zr, Na, K, Al, Ca and Mg. 

The essential microelements are only required in trace amounts (see also p.2). This group includes iron (Fe), zinc (Zn), manganese (Mn), copper (Cu), cobalt (Co), chromium (Cr), selenium (Se), and molybdenum (Mo). Fluorine (F) is not essential for life, but does promote healthy bones and teeth. It is still a matter of controversy whether vanadium, nickel, tin, boron, and silicon also belong to the essential trace elements. 

Some typical and preferred heavy and trace element concentrations for soils and municipal composts are shown in Table 5.3. The levels in soils are typical for dilute aqueous extractants such as 0.05 M EDTA, 0.5 M acetic acid, hot water for boron, and, for molybdenum, Tamm s reagent (acid ammonium oxalate Reisenauer, 1965). Tables in the literature often give total values obtained spectrographically, by XRF, or by extraction with hot... 

Sihcon of hyperpurity, doped with trace elements, such as boron, phosphorus, arsenic, and gadium is one of the best semiconductors. They are used in transistors, power rectifiers, diodes and solar ceds. Sihcon rectifiers are most efficient in converting a-c to d-c electricity. Hydrogenated amorphous sihcon converts solar energy into electricity. 

Another study of the variation of trace element concentrations with ashing time at 500°C in covered and uncovered platinum crucibles indicated that ashing time had no effect (Table V). As previously noted, the loss of boron from the uncovered crucibles stabilized at a relatively constant concentration in less than 5 hrs. Molybdenum and vanadium, which show losses with increasing temperatures, show no apparent ashing time dependence. 

Figure 1-17 Elements known to be essential to living things (after da Silva and Williams157). Essential elements are enclosed within shaded boxes. The 11 elements-C, H, O, N, S, P, Na, K, Mg, Ca, and Cl-make up 99.9% of the mass of a human being. An additional 13 are known to be essential for higher animals in trace amounts. Boron is essential to higher plants but apparently not to animals, microorganisms, or algae.

TRACE ELEMENT (Mlcronutrient). An element essential to plant and animal nutrition in trace concentration, i.e., minute fractions of 1% (1000 ppm or less). Plants requite iron, copper, boron, zinc, manganese, potassium, molybdenum, sodium, and chlorine. Animals require iron, copper, manganese, cobalt, selenium, and potassium. Such elements are also called micronutrients. Do not confuse with tracer. 

D. Logie (83) described a new analytical separation technique by applying ion-exchange membranes, which can be used for the determination of boron in sodium metal. By treatment with water, the Na is converted to NaOH, borate being formed from the boron. When the solution is introduced in the anode chamber of a two-cell apparatus fitted with a negative membrane, the Na+ ion is transported to the cathode chamber, whereas the borate anion remains in the anode chamber. In general this method can be applied, if the trace element yields an ion with a charge which opposite to that of the main component. 

Noll, P.D. Jr., Newsom, H.E., Leeman, W.P. and Ryan, J.G. (1996) The role of hydrothermal fluids in the production of subduction zone magmas evidence from siderophile and chalcophile trace elements and boron. Geochimica et Cosmochimica Acta, 60(4), 587-611. 

The variable isotopic compositions (especially for Pb) reveal geochemi-cally heterogeneous sources. The origin of this heterogeneity is debated and may derive either from shallow mantle processes, such as variable me-tasomatic modifications of the lithosphere by asthenospheric melts, or from mixing between a deep-mantle plume and asthenosphere-lithosphere material. Etna and Ustica show some trace element and isotopic characteristics (e.g. Rb/Nb, Ce/Pb, and boron isotopes), indicative of a contribution from subduction-derived components. 

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