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101.
I. Orlic R. Siegele D. D. Menon S. J. Markich D. D. Cohen R. A. Jeffree D. C. McPhail A. Sarbutt E. Stelcer 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2002,190(1-4):439-444
Nuclear milli and microprobes at the Australian Nuclear Science and Technology Organisation (ANSTO) were used to determine lead accumulation in native Australian plants and animals. Three species of eucalypt plants (Eucalyptus camaldulensis, Eucalyptus globulus and Eucalyptus lesouefii), one species of salt bush (Atriplex burbhanyana) and one species each of acacia (Acacia saligna) and estuarine crocodiles (Crocodylus porosus) were investigated. Experimentally grown plants were subjected to a nutrient solution with a pH of 5 and spiked with a 200 μmol concentration of Pb. Lead concentrations in leaves of both E. globulus and E. camaldulensis showed an almost exponential decrease from the base of the main vein to the tip. Similarly, Pb concentrations decreased from the main vein to secondary veins. Concentrations of essential elements such as K, Fe, Zn and Br in the main and secondary veins were constant within experimental uncertainty. In contrast, the concentrations of Pb in the leaf veins of E. lesouefii were much lower and showed no systematic pattern. In stem and root samples the highest concentration of Pb was found in roots and stem of E. globulus and A. burbhanyana followed by E. camaldulensis. Some Pb was found in roots of A. saligna and only very low concentration in stem of the same plant. More detailed analysis of thin cross-sectional samples of roots and stem showed that Pb is present in much higher concentration in the growth area of the plant structure (i.e. meristemic region) and in relatively low concentration within the pith region and outer cortex. The osteoderms (dermal bones) of estuarine crocodiles, exposed to lead ammunition in food from the hunting activities of traditional Aboriginal owners, were sampled at two sites in Kakadu National Park, northern Australia. PIXE analyses showed enhanced, but relatively constant, ratios of Pb/Ca in the annual laminations. This was consistent with both their history of long term exposure to elevated anthropogenic Pb sources and the hypothesis that the osteoderm can be used as an archive of the crocodile's exposure to Pb during its life. 相似文献
102.
C Bogdan H Thüring M Dlaska M R?llinghoff G Weiss 《Canadian Metallurgical Quarterly》1997,159(9):4506-4513
IL-13 is a cytokine produced by T lymphocytes, mast cells, basophils, and certain B cell lines that up-regulates or inhibits various macrophage functions. In the present study we analyzed the mechanisms of suppression of nitric oxide (NO) release by IL-13 in the macrophage cell line J774A.1 and in thioglycolate-elicited mouse peritoneal macrophages. In both cell types efficient reduction (>80%) of NO production required treatment of the macrophages with IL-13 for at least 7 h before stimulation with IFN-gamma and LPS. In J774A.1 cells, increasing concentrations of IFN-gamma partially antagonized the suppression mediated by IL-13, whereas in peritoneal macrophages, the inhibitory effect of IL-13 was largely independent of the concentrations of IFN-gamma and LPS. In J774A.1 cells, IL-13 strongly reduced both the mRNA and protein levels of inducible nitric oxide synthase (iNOS, NOS-2), as determined by Northern blot analysis and immunoprecipitation. In peritoneal macrophages, in contrast, IL-13 decreased iNOS protein and enzyme activities after 8 to 48 h of stimulation, without altering the expression of iNOS mRNA. Pulse labeling with [35S]methionine revealed that IL-13 caused a 4.7-fold reduction of the de novo synthesis of iNOS protein in these cells. These data demonstrate for the first time that IL-13 is capable of regulating iNOS at both the mRNA and translational levels and underline the important influence of the macrophage population when studying mechanisms of cytokine functions. 相似文献
103.
MN Bogdan 《Canadian Metallurgical Quarterly》1998,98(3):35-38
The range of prevalence rates for borderline mental disorders is very wide: from 17 to 210 cases per 1000 population. Considerable differences are explained both by a problem of detection of such patients and by certain diagnostic difficulties. Most clinical notions concerning borderline states are insufficiently definite and this has considerable influence on the results of epidemiologic researches. Analysis of the frequency of clinical diagnoses in two Moscow primary care out-patient clinics showed considerable differences which has disappeared under ICD-10 diagnosis. 相似文献
104.
Cristofor I. Simionescu Bogdan Simionescu Monica Leanca Carmen Ananiescu 《Polymer Bulletin》1981,5(2):61-66
Summary Investigations carried out in plasma-induced polymerization (copolymerization) led to the idea of the existence of living macroradicals. Their presence in both homogeneous and heterogeneous media was experimentally proved and theoretically explained and their use as macromolecular initiators in polymerization processes is exemplified.Dedicated to Prof. Dr. Dragutin Fle at the Occasion of his 60th Anniversary 相似文献
105.
Re‐ignition behaviour of charred solid fuels after extinction by water is studied. In this communication the effect of material porosity on re‐ignition is investigated. A surrogate ceramic material is used so as to separate the pyrolysis and combustion processes from those associated with heat transfer. Experimental data are reported for different sample thickness and porosity, and varying heat flux and water application time. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
106.
107.
Bogdan S. Chlebus 《Theoretical computer science》1982,21(2):179-212
The satisfiability problems of propositional algorithmic logic and propositional dynamic logic are shown to be complete in the classes of languages accepted in polynomial space by the deterministic and alternating Turing machines respectively. Explicit upper and lower bounds on the space complexity are calculated. Exponential lower bounds on the space complexity of the satisfiability problems of these logics extended by adding a certain program connective are proved. 相似文献
108.
Chen C Kwak ES Stein B Kao CC Dragnea B 《Journal of nanoscience and nanotechnology》2005,5(12):2029-2033
In-vitro self-assembly conditions known to result in generating infectious virions have been used in vitro to reassemble bromovirus capsid proteins around negatively charged gold nanoparticles cores. We discuss here the optical properties (elastic light scattering) and the influence of the core size and of the functional moiety on the resulting virus-like particles. Our results indicate that the formation of a closed shell, as opposed to an amorphous protein coat, does occur and that the shell/core interactions can be tuned using different coatings on the nanoparticle core. Such studies may lead to real-time monitoring of viral traffic on the scale of a single virus, as well as to the possibility of chemical sensing along the intracellular and intercellular viral pathways and contribute to a better understanding of the virus transport and cellular compartmentalization. 相似文献
109.
A. Biris D. Lupu R.V. Bucur E. Indrea G. Borodi M. Bogdan 《International Journal of Hydrogen Energy》1982,7(1):89-94
The addition of aluminium to a mixture of Mg-Cu (2:1 atomic ratio) leads by melting to the formation of increasing amounts of Mg(Cu,Al)2 where aluminium substitutes for copper atoms in the MgCu2 lattice, raising the lattice parameter. The hydrogen absorbed in this phase is strongly bounded, as proved by desorption isotherms and nuclear magnetic resonance data. 相似文献
110.
Mihaela Badea Rodica Olar Dana Marinescu Gina Vasile Bogdan Jurca Augustin M. Madalan Marius Andruh 《Inorganic chemistry communications》2009,12(6):555-557
The reaction between NiCO3 · Ni(OH)2, acrylic acid and ethylenediamine in a 2:4:1 molar ratio affords the binuclear complex, [Ni2(EDDP)2(H2O)2] · 2H2O 1. The organic ligand, EDDP2? (the dianion of the ethylenediamine-N,N-dipropionic acid ligand), results from the addition of one amine group to the carbon–carbon double bonds of two acrylato ions. The crystal structure of 1 consists of neutral centrosymmetric entities, with the nickel ions connected by two carboxylato groups, each one acting as a monoatomic bridge. The intramolecular Ni?Ni distance is 3.212 Å. The metal ions exhibit an octahedral geometry. The cryomagnetic investigation of 1 reveals an antiferromagnetic coupling of the nickel(II) ions (J = ?21.8 cm?1, H = ?JSNi1SNi2). 相似文献