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PURPOSE: This research evaluated clinical, histological, and radiological osseous regeneration in a critical-sized bilateral cortico-medullary osseous defect in model rabbits from New Zealand after receiving a hydroxyapatite matrix and polylactic polyglycolic acid (HA/PLGA) implanted with human dental pulp stem cells (DPSCs). METHODS: Eight New Zealand rabbits with bilateral mandibular critical-sized defects were performed where one side was treated with an HA/PLGA/DPSC matrix and the other side only with an HA/PLGA matrix for 4 weeks. RESULTS: An osseointegration was clinically observed as well as a reduction of 70% of the surgical lumen on one side and a 35% on the other. Histologically, there was neo-bone formation in HA/PLGA/DPSC scaffold and angiogenesis. A bone radiodensity (RD) of 80% was radiologically observed achieving density levels similar to mandibular bone, while the treatment with HA/PLGA matrix achieves RD levels of 40% on its highest peaks. CONCLUSIONS: HA/PLGA/DPSC scaffold was an effective in vivo method for mandibular bone regeneration in critical-sized defects induced on rabbit models.

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The B-site ordered double perovskite Ba2CaOsO6 was studied by dc magnetic susceptibility, powder neutron diffraction and muon spin relaxation methods. The lattice parameter is a = 8.3619(6) Å at 280 K and cubic symmetry [Formula: see text] is retained to 3.5 K with a = 8.3462(7) Å. Curie-Weiss susceptibility behaviour is observed for T > 100 K and the derived constants are C = 0.3361(3) emu K mol(-1) and ΘCW = -156.2(3) K, in excellent agreement with literature values. This Curie constant is much smaller than the spin-only value of 1.00 emu K mol(-1) for a 5d(2) Os(6+) configuration, indicating a major influence of spin-orbit coupling. Previous studies had detected both susceptibility and heat capacity anomalies near 50 K but no definitive conclusion was drawn concerning the nature of the ground state. While no ordered Os moment could be detected by powder neutron diffraction, muon spin relaxation (µSR) data show clear long-lived oscillations indicative of a continuous transition to long-range magnetic order below TC = 50 K. An estimate of the ordered moment on Os(6+) is ∼ 0.2 µB, based upon a comparison with µSR data for Ba2YRuO6 with a known ordered moment of 2.2 µB. These results are compared with those for isostructural Ba2YReO6 which contains Re(5+), also 5d(2), and has a nearly identical unit cell constant, a = 8.36278(2) Å-a structural doppelgänger. In contrast, Ba2YReO6 shows ΘCW = - 616 K, and a complex spin-disordered and, ultimately, spin-frozen ground state below 50 K, indicating a much higher level of geometric frustration than in Ba2CaOsO6. The results on these 5d(2) systems are compared to recent theory, which predicts a variety of ferromagnetic and antiferromagnetic ground states. In the case of Ba2CaOsO6, our data indicate that a complex four-sublattice magnetic structure is likely. This is in contrast to the spin-disordered ground state in Ba2YReO6, despite a lack of evidence for structural disorder, for which theory currently provides no clear explanation.

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(57)Fe Mössbauer spectroscopy has been used to investigate the structural and magnetic phase transitions of CaFe2As2 (T(N) = 173 K) single crystals. For this compound we found that V(ZZ) is positive and parallel to the c-axis of the tetragonal structure. For CaFe2As2 a magnetic hyperfine field B(hf) was observed at the (57)Fe nucleus below T(N) ~173 K. Analysis of the temperature dependence of B(hf) data using the Bean-Rodbell model shows that the Fe spins undergo a first-order magnetic transition at ~173 K. A collinear antiferromagnetic structure is established below this temperature with the Fe spin lying in the (a, b) plane. Below T(N) the paramagnetic fraction of Fe decreases down to 150 K and for lower temperatures all the Fe spins are magnetically ordered.

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(57)Fe Mössbauer spectroscopy has been used to investigate the magnetic order of non-superconducting NdFeAsO (T(N) = 140 K) and superconducting NdFeAsO(0.88)F(0.12) (T(c) = 45 K). A magnetic hyperfine field B(hf) was observed at the (57)Fe nucleus below T(N)∼140 K for NdFeAsO. Below ∼2 K an increase of B(hf) relative to the saturation value was attributed to the transferred B(hf) at the Fe site resulting from the collinear antiferromagnetic (AF) spin structure of the Nd moments. The analysis of the spectra is consistent with a commensurate AF order of Fe spins. No  B(hf) is observed in superconducting NdFeAsO(0.88)F(0.12) down to 1.5 K.

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Inflammatory processes are mediated by many cellular events involving different cell types (leukocytes, monocytes, stromal cells, etc.). Numerous soluble mediators regulate these reactions, including leukaemia inhibitory factor (LIF), a cytokine which may play an important role in inducing acute-phase protein synthesis by hepatocytes during inflammation. This study was designed to determine the effects of LIF on the human monocyte/macrophage lineage and provide a better definition of its behaviour during systemic inflammation. In-vitro exposure of human long-term bone marrow cultures to recombinant human LIF significantly increased (about two-fold) the number of multinucleated cells (MNC) formed after three weeks of culture. These LIF-induced MNC expressed tartrate-resistant acid phosphatase, and LIF increased this intracellular activity by about 50%. MNC displayed phagocytotic activity but were unable to degrade sperm whale dentin or respond to human calcitonin. They did not possess the main characteristics of osteoclasts and were in fact macrophage polykaryons. Our results demonstrate for the first time that LIF can induce macrophage polykaryon formation from human bone marrow culture, suggesting that this factor not only produces leukocytes but also has a direct influence on the monocyte/macrophage lineage.

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