Stimulation of bovine monocyte-derived macrophages with lipopolysaccharide, interferon-ɣ, Interleukin-4 or Interleukin-13 does not induce detectable changes in nitric oxide or arginase activity

Background: Bacterial lipopolysaccharide and interferon-γ stimulation of rodent macrophages in vitro induces up-regulation of inducible nitric oxide synthase, whereas interleukin-4 stimulation results in increased activity of arginase-1. Thus different stimulants result in differing macrophage phenotypes, appropriate for responses to a range of pathogens. The current study was conducted in order to determine whether bovine macrophages derived from monocytes and spleen respond similarly. Results: Lipopolysaccharide and interferon-γ did not induce detectable increases in nitric oxide production by bovine monocyte-derived or splenic macrophages in vitro. Similarly, interleukin-4 and interleukin-13 did not affect arginase activity. However, changes in transcription of genes coding for these products were detected. Conclusion: Differences between macrophage activation patterns exist between cattle and other species and these differences may occur during the post-transcription phase

Heat Transport in Spin Chains with Weak Spin-Phonon Coupling.

The heat transport in a system of S=1/2 large-J Heisenberg spin chains, describing closely Sr(2)CuO(3) and SrCuO(2) cuprates, is studied theoretically at T≪J by considering interactions of the bosonized spin excitations with optical phonons and defects. Treating rigorously the multiboson processes, we derive a microscopic spin-phonon scattering rate that adheres to an intuitive picture of phonons acting as thermally populated defects for the fast spin excitations. The mean-free path of the latter exhibits a distinctive T dependence reflecting a critical nature of spin chains and gives a close description of experiments. By the naturalness criterion of realistically small spin-phonon interaction, our approach stands out from previous considerations that require large coupling constants to explain the data and thus imply a spin-Peierls transition, absent in real materials

The formation of the superheavy hydrogen isotope H-6 in the absorption of stopped pi(-)-mesons by nuclei

An experimental search for the superheavy hydrogen isotope H-6 was conducted through studying the absorption of stopped pi(-)-mesons by Be-9 and B-11 nuclei. A structure in the missing mass spectrum caused by the resonance states of H-6 was observed in three reaction channels, namely, Be-9(pi(-), pd)X, B-11(pi(-), d(3)He)X, and B-11(pi(-), p(4)He)X. The parameters of the lowest state E-r = 6.6 +/- 0.7 MeV and Gamma = 5.5 +/- 2.0 MeV (E-r is the resonance energy with respect to the disintegration into the triton and three neutrons) are evidence that H-6 is a more weakly bound system than H-4 and H-5. Three excited states of H-6 were observed. Their resonance levels (E-1r = 10.7 +/- 0.7 MeV, Gamma(1r) = 4 +/- 2 MeV, E-2r = 15.3 +/- 0.7 MeV, Gamma(2r) = 3 +/- 2 MeV, and E-3r = 21.3 +/- 0.4 MeV, Gamma(3r) = 3.5 +/- 1.0 MeV) are energetically capable of disintegrating into six free nucleons. (C) 2003 MAIK "Nauka / Interperiodica"