The concept of hidden Fermi surface nesting was introduced to explain the general observation that certain low-dimensional metals with several partially filled bands exhibit charge density wave (CDW) instabilities, although their individual Fermi surfaces do not reveal the observed nesting vectors. This concept was explored by considering the Fermi surfaces of the purple bronze AMo(6)O(17) (A =...

Ships transport about 80 percent of world trade and transfer approximately three to five billion tons of ballast water internationally every year. Due to the likely presence of pollutants, the ballast water discharged by ships can have negative effects on aquatic ecosystems. This study was conducted on 10 ships that entered the Bushehr port to determine the effectiveness of the ballast water ex...

Zinc (Zn) is an essential, common metal in animal tissues. Zn levels were elevated in only four tissues after Zn administration, the highest increase being in the pancreas. Zn concentration was increased by metallothionein induction. Metallothionein-bound Zn significantly reduced the toxicity of the metals Cd, Cu and Hg. It should be noted that tissue Zn levels are different in experimental ani...

We describe techniques for controlling contamination in the sampling and analysis of human serum for trace metals. The relatively simple procedures do not require clean-room conditions. The atomic absorption and atomic emission methods used have been applied in studying zinc, copper, chromium, manganese, molybdenum, selenium, and aluminum concentrations. Values obtained for a group of 16 normal...

recently, grave explosions in the oil and gas transport tubes, as well as, the rapid failure of the machine parts in service, were caused by hydrogen cracking. during solidification of metals, in casting ,welding, cathodic charging, etc., the hydrogen can enter in metals and cause premature cracking. the hydrogen embrittlement in metals is accompanied with a charge in the type of fracture surfa...

Trace elements play an important role in human health and disease. Trace elements participate in tissue, cellular and subcellular function. These include immunoregulation by both humoral and cellular mechanism, nerve conduction, muscle contraction, membrane potential regulation, and mitochondrial activity, among others (1, 2). Although these trace elements constitute a relatively small amount o...

Inorganic arsenic is a potent carcinogen and environmental pollutant. More than one hundred million people are reported to be exposed to elevated concentrations of arsenic mainly via drinking water. Essential trace elements can affect toxicity of metals by interacting with metals at the primary site of action and can also modify the body's response to toxic metals by altering their metabolism a...

Mining activities can lead to the generation of large quantities of heavy metal laden wastes which are released in an uncontrolled manner, causing widespread contamination of the ecosystem. Though some heavy metals classified as essential are important for normal life physiological processes, higher concentrations above stipulated levels have deleterious effects on human health and biota. Bacte...