The statistical treatment of resonating covalent bonds in metals, previously applied to hypoelectronic metals, is extended to hyperelectronic metals and to metals with two kinds of bonds. The theory leads to half-integral values of the valence for hyperelectronic metallic elements.

Rare earth metals are used in semiconductors, solar cells and catalysts. This review focuses on the background of oxide metallurgy technologies, the chemical and physical properties of rare earth (RE) metals, the background of oxide metallurgy, the functions of RE metals in steelmaking, and the influences of RE metals on steel microstructures. Future prospects for RE metal applications in steel...

To examine the effects of dissolved organic matter on metal bioavailability, uptake of trace metals (Cd, Co, Hg, Cr, Ag, Zn) by American oysters (Crassostrea virginica) was compared between treatments with different dissolved organic carbon (DOC) concentrations and contrasting low molecular weight (LMW, 1 kDa) and high molecular weight (HMW, 1 kDa-0.2 micron) DOC fractions, using radiotracer te...

The concentration of metals by marine phytoplankton, assessed for diverse species in laboratory culture experiments with radiotracer methodology and taken together with literature values for other metals, was analyzed in light of geochemical models describing particle surface chemistry. Concentration factors vary among the metals from -0 to = 106, and there are only modest differences (less tha...

Brassinosteroids play a significant role in the amelioration of various abiotic and biotic stresses. In order to elaborate their roles in plants subjected to heavy metals stress, Chlorella vulgaris cultures treated with 10(-8) M brassinolide (BL) were exposed to 10(-6)-10(-4) M heavy metals (cadmium, lead and copper) application. Under heavy metals stress, the growth and chemical composition (c...

Effects of contaminants on communities are difficult to assess and poorly understood. We analyzed in situ effects of trace metals and common environmental variables on benthic macroinvertebrate communities in floodplain lakes. Alternative measures of trace metal availability were evaluated, including total metals, metals normalized on organic carbon (OC) or clay, simultaneously extracted metals...

Modern analytical methods today have been proven to be very useful for accurate determination of metals. It is required to determine optimum concentration of some essential metals as deficiency or excess may cause abnormalities in body. Also there is strict legal requirement to monitor and control levels of metals in food, environment and medicines. Estimation of concentration of metals in body...

Introduction Bacteria may carry determinants of resistance to a number of heavy metals, including silver, bismuth, cadmium, cobalt, copper, mercury, lead, nickel, thallium or zinc cations and the oxyanions of arsenic, chromium, antimony, tellurium or tungsten. Such resistance determinants have been reviewed extensively [ 1-41. Bacterial resistance to heavy metals is conferred by specific resist...

It is obvious that heavy metals toxicity to humans is as a result of long term or extreme level exposure to pollutants common in the environment including the air, water, food and many consumer products like the cosmetics and toiletries .In this study, we measured the levels of toxic metals in different hair dye products sold at local shops in Baghdad, Iraq. The hair dyes included twelve sample...

In order to understand the heavy metals accumulation and transfer in a plant-soil system in sewage sludge applied soils, 15 familiar garden plants (including 7 herbages, 5 shrubs and 3 arbor species) were planted in soil with sewage land application at the experimental site in Shanghai, China. The experiment measured the changes in 7 heavy metals (Zn, Cu, Ni, Cd, Pb, Cr and As) fractions and co...