As urinary excretion of methylmercury is very small, methylmercury concn in urine is easily masked by the presence of inorganic mercury. Thus, urine concn of mercury is not a good index of methylmercury body burden or of methylmercury concn in the critical organ. /Methylmercury compounds/
Systemic - The central nervous system, including the brain, is the principal target tissue for this group of toxic compounds. Severe poisoning may produce irreversible brain damage resulting in loss of higher functions. The effects of chronic poisoning with alkyl mercury compounds are progressive. In the early stages, there are fine tremors of the hands, and in some cases, of the face and arms. With continued exposure, tremors may become coarse and convulsive; scanning speech with moderate slurring and difficulty in pronunciation may also occur. The worker may then develop an unsteady gait of a spastic nature which can progress to severe ataxia of the arms and legs. Sensory disturbances including tunnel vision, blindness, and deafness are also common. A later symptom, constriction of the visual fields, is rarely reversible and may be associated with loss of understanding and reason which makes the victim completely out of touch with his environment. Severe cerebral effects have been seen in infants born to mothers who had eaten large amounts of methyl mercury-contaminated fish. /Methyl mercury compounds/
IN HUMANS THE NEUROTOXIC SYMPTOMS OF METHYL MERCURY SALTS, THE HUNTER-RUSSEL SYNDROME, INVOLVE FOCAL CEREBRAL & CEREBELLAR ATROPHY. THE GRANULAR CELL LAYER OF NEOCEREBELLUM IS AFFECTED FOLLOWED BY CORTICAL ATROPHY OF AREA STRIATA, WHICH LEADS TO BLINDNESS. /METHYL MERCURY SALTS/
EXPERIMENTALLY, BOTH FERRETS & GOSHAWKS HAVE BEEN POISONED BY FEEDING THEM WITH FLESH OF CHICKENS FED WITH METHYLMERCURY DICYANDIAMIDE. ... CHICKENS THEMSELVES SHOWED NO SIGNS OF POISONING. DOGS HAVE ALSO BEEN POISONED AFTER CONSUMING FLESH OF PIGS WHICH HAD DIED OF MERCURY POISONING.
THE MINIMAL FATAL ORAL DOSE OF METHYLMERCURIC DICYANAMIDE TO PIGS WAS 20 MG/KG. SIGNS OF TOXICOSIS WERE OBSERVED IN PIGS GIVEN SINGLE DOSES AS LOW AS 5 MG/KG, BUT NOT IN PIGS GIVEN 2.5 MG/KG. THE MINIMAL FATAL REPETITIVE ORAL DOSE WAS 0.65 MG/KG AFTER 26 OR 30 DAILY DOSES. NEUROLOGIC DISTURBANCES WERE OBSERVED.
Alloying effect on heat of hydride and deuteride formation for Pd-based binary alloys
摘要：
Absorption and desorption isotherms of protium and deuterium were measured for Pd-based alloys as Pd((1-x))AE(x), where AE = Co, Ni, Cu, Rh, Ag, Pt and An. It was observed that the heat of hydride formation decreased with increasing AE content for Co, Ni, Cu, Rh, Pt and An, although the extent of the increase differed from each other. According to Lasser, on the other hand, alloying of Ag caused to increase the heat of hydride formation. These features were analyzed from electronic structures of the alloys inspected by use of DV-X alpha package, where the inspections were carried out for small clusters as Pd((14-y))AE(y). The DV-X alpha calculations showed that the energy of the highest occupied molecular orbital of the clusters change almost linearly with their composition, suggesting that the Fermi energy of respective alloys changes in the similar manner. By assuming the Fermi energy of Pd((1-x))AE(x) to be arithmetic means of the Fermi energies of pure Pd and AE, a linear relation was found between the observed enthalpy change of hydride formation and the assumed Fermi energy. (c) 2006 Elsevier B.V. All rights reserved.
Nd1.85Ce0.15Cu1-xMnxO4 samples with doping level up to 30% have been synthesized. The influence of Mn on crystal structure, superconductivity and normal-state magnetic properties of Nd1.85Ce0.15Cu1O4 (NCCO) is studied. Different from the doping effect in others high-T-c cuprates, Mn doping in NCCO causes an orthorhombic-to-tetragonal structure transition, and significantly suppresses the superconductivity for both T-c and Meissner volume. The effective magnetic moment per lattice cell increases with increasing Mn content, resulting in an antiferromagnetic correlation at high doping levels and a complete destroy of superconductivity. (C) 2007 Elsevier B.V. All rights reserved.
