Electrical properties of monoazacrown ether-substituted phthalocyanines

D.c. conductivities of polycrystalline monoazacrown ether-substituted phthalocyanines (M=2H, Ni, Zn, Pb, Cu) and diphthalocyanine (M=Lu) are measured as Au-MPc-Au sandwiches to be of the order 10^–10–10^–12 S m^–1. Chemical doping with oxidants (e.g. NOBF₄) and enhancing the stacking of planar phthalocyanine moieties through the formation of alkali metal adducts with sodium and potassium ions leads to increase in conductivity of the order 10¹–10². The low conductivity and the diamagneticity of the bis(phthalocyaninato)-lutetium can be ascribed to the lack of radical nature in LuH(Pc)₂. For the a.c. conductivities, lead and lutetium complexes form a group with higher conductivities and the rest show lower conductivity. The conduction activation energies calculated from Arrhenius plots exhibit the lowest value (0.40 eV) for the lutetium compound.Part of this work was presented at NATO-ASI on Semiconductor Materials and Processing Technologies, Erice, Sicily, 1–13 July 1991.     

The structure of a cast dental Ni-Cr-Be alloy

The structure of a typical dental Ni-Cr-Be alloy with 1.8 wt% Be has been investigated by SEM and TEM as well as by quantitative X-ray microanalyses in both instruments. Due to its low atomic weight the atomic fraction of Be is as high as 0.10. During solidification beryllium segregates substantially, and a large volume fraction of the casting is made up of a eutectic with coarse ( 1 µm diameter) alternating rods of fcc Ni-Cr and NiBe with a CsCl-type structure (ordered bcc). Smaller ( 0.1 µm diameter) rods of NiBe are precipitated in matrix in the solid state. Microanalyses of the NiBe rods show that they have a low chromium content ( 1.5 wt%). The cube boundary planes of the ordered b cc and fcc structures have a slight difference in orientation of about 7° which is most probably due to a small coherency misfit of the two types of lattices. The 100 directions in cube boundary plane of the fcc structure are nearly parallel to the 110 directions of the ordered bcc cube boundary plane. Sometimes another and more complex relationship between the two lattices occurs. The alloy contains 3.9 wt% Al which gives rise to numerous small ( 10 nm), spherical, ordered particles of Ni₃Al both in matrix as well as in the fcc eutectic rods.     

Standardised Nordic questionnaires for the analysis of musculoskeletal symptoms

Standardised questionnaires for the analysis of musculoskeletal symptoms in an ergonomic or occupational health context are presented. The questions are forced choice variants and may be either self-administered or used in interviews. They concentrate on symptoms most often encountered in an occupational setting. The reliability of the questionnaires has been shown to be acceptable. Specific characteristics of work strain are reflected in the frequency of responses to the questionnaires.     

The Effect of Small Additions of Fe and Heavy Deformation on the Precipitation in an Al–1.1Mg–0.5Cu–0.3Si At. Pct Alloy

Metallurgical and Materials Transactions A - The effect of 0.03 and 0.08 at. pct Fe additions on the formation of secondary phases in an Al–1.1Mg–0.5Cu–0.3Si at. pct alloy was...     

Passivation of the aluminium cathode during deposition of aluminium from aluminium chloride-sodium chloride melts

The kinetics of aluminium deposition from NaCl-AlCl₃ melts (c_AlCl3 < 10 mol%) contained in alumina crucibles was studied by linear sweep voltammetry and potential step amperometry at temperatures around 820°C. At low concentrations (c_AlCl3 < 0.4 mol%) the reduction of AlCl₃ on liquid aluminium has been found to be diffusion controlled. At higher concentrations a passivation of the aluminium electrode was observed during the deposition reaction. The passivation appears to be caused by precipitation of alumina from supersaturated melt in the diffusion layer at the aluminium cathode.     

Nickel-catalyzed hydrogenation: A study of the poisoning effect of halogen-containing compounds

The poisoning effect of various halogen compounds on a nickel-based hydrogenation catalyst has been investigated. While alkyl monochlorides did not affect the catalyst activity, alkyl monobromide and-iodide had a strong poisonous effect. Vicinal dichlorides, 1,1-dichlorides, and HC1 also poisoned the catalyst. It is shown that with chlorine containing compounds, the poisoning mechanism involves a fission of the carbon-chlorine bond with the formation of HC1, while bromine and iodine compounds adsorb to the catalyst surface as such in a simple equilibrium reaction. A mackerel oil previously shown to exhibit three kinetically distinguishable poisoning effects has been further examined, and it is shown that its content of halogens can probably account for the observed poisoning pattern.     

The influence of food emulsifiers on fat and sugar dispersions in oils. III. Water content,purity of oils

The influence of water on the interactions between fat and sugar crystals dispersed in triglyceride (vegetable) oils was qualitatively estimated from sedimentation and rheological experiments. The experiments were performed both with and without food emulsifiers (monoglycerides and lecithins) present in the oil. The effects of minor natural oil components (nontriglycerides) on the interactions and on emulsifier adsorption to the crystals were examined by comparing a commercial refined oil and a chromatographically purified oil. The results show that water generally increases the adhesion between fat and sugar crystals in oils and also increases the surface activity of the oil-soluble food emulsifiers. Minor oil components give a small increase in the adhesion between fat and sugar crystals in oils, but do not influence the adsorption of food emulsifiers in any systematic way.     

Dietary fish oils and long-term malaria protection in mice

Previous studies indicate a suppressive influence of fish oils on rodent malaria. The present work was carried out to study (i) the dose-effect relation between dietary fish oils and lethality of primary malaria infection in mice; (iii) the modifying influence of vitamin E; and (iii) the effect of previous fish oil feeding on parasitemia and lethality of a rechallenge infection. For two or four weeks, groups of weanling male mice were fed a standard laboratory diet or one of eight purified diets containing various amounts of fish oil (providing 6–21% of energy). The diets were prepared with and without vitamin E. After the two-or four-week feeding period, the mice were injected intraperitoneally withPlasmodium yoelii yoelii-infected erythrocytes. Six months after the primary infection (four months after discontinuing fish oil feeding), the surviving mice were again injected intraperitoneally with parasitized red blood cells (or even better—erythrocytes, erythrocytes are used elsewhere). Primary malaria infection was lethal in mice fed standard diet alone or with fish oil and vitamin E added. In contrast, feeding a fish oil-based diet without vitamin E improved survival to at least 70% if the mice had been fed these diets for four weeks. Protection against malaria did not seem to be related to the fish oil dose used. Regardless of the previous fish oil dose, all the mice surviving the primary infection survived the rechallenge infection with low parasitaemias. The results suggest that the prooxidant nature of highly unsaturated fatty acids in fish oils may beneficially influence malaria infection, and may also increase the resistance against reinfection for some time after discontinuing fish oil intake.     

Effect of chromium aging on the structural and thermal properties of chromium polyacrylate

The effects of aging time of Cr(III) solutions on the structural, thermal, magnetic, and morphological properties of chromium polyacrylate complexes were studied. Chromium retention was found to increase with longer aging periods. IR spectra revealed the formation of polychelate structures with noticeable changes on aging. The interaction of multivalent, polynuclear Cr(III) species with the polymer backbone resulted in a decrease in thermal stability for the complexes prepared from olated chromium solutions. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 490–493, 2005