1,491 research outputs found

    Utjecaj lantana na mikrostrukturu i svojstva čelika ASTM A216

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    In order to satisfy the rudder horn casting standards of the International Association of Classification Societies, the properties of ASTM A216 steel should be improved. Therefore, in this article the rudder horn casting and accompanying specimens were cast moulded by arc furnace smelting, external refining, and modification treatment of the molten steel by lanthanum. The samples were first underwent normalizing treatment at 900 °C for 10 hours, then air cooled, followed by tempering treatment at 600 °C for 7 hours and samples were air cooled again. The mechanical properties and microstructures of the samples were measured. The crystallography relationships between lanthanum compounds formed in the molten steel and primary δ-Fe were analysed. The nucleation effect of lanthanum compounds as a heterogeneous nucleation core of primary δ-Fe were calculated and discussed based on two-dimensional mismatch theory. The results indicated that the strip MnS inclusions in ASTM A216 steel became granular rare earth compound inclusions due to La. The refined microstructures were obtained by a synergistic effect of the enhanced condensate depression and the nucleation rate of melt and La compounds as the heterogeneous nucleation caused by La.Da bi se zadovoljili standardi Međunarodnog udruženja klasifikacijskih zavoda (IACS) za lijevanje krmenog roga, potrebno je poboljšati svojstva čelika ASTM A216. Odljevci krmenog roda i prateći uzorci, nakon taljenja čelika u elektrolučnoj peći, rafiniranja i dodatka lantana, izrađeni su lijevanjem čelika u kalupe. Uzorci su prvo normalizirani zagrijavanjem 10 sati na 900 °C, ohlađeni na zraku, potom podvrgnuti popuštanju 7 sati na 600 °C i ponovno ohlađeni na zraku. Određena su mehanička svojstva uzoraka i proučena mikrostruktura. Analizirana je sličnost kristalne građe spojeva lantana nastalih u rastaljenom čeliku i δ-željeza. Izračunata je učinkovitost lantanovih spojeva kao podloge za heterogenu nukleaciju δ-željeza na temelju dvodimenzijskog nepodudaranja struktura. Dodatkom lantana vrpčasti uklopci MnS postaju zrnasti uklopci spoja rijetke zemlje. Finija mikrostruktura dobivena je sinergijskim djelovanjem povećane depresije kondenzata i brže nukleacije uz lantan

    Mesangial cells of lupus-prone mice are sensitive to chemokine production

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    Infectious antigens may be triggers for the exacerbation of systemic lupus erythematosus. The underlying mechanism causing acceleration and exacerbation of lupus nephritis (LN) is largely unknown. Bacterial lipopolysaccharide (LPS) is capable of inducing an accelerated model of LN in NZB/W mice, featuring diffuse proliferation of glomerular resident cells. We hypothesized that mesangial cells (MCs) from LN subjects are more responsive to LPS than normal subjects. Cultured primary NZB/W and DBA/W (nonautoimmune disease-prone strain with MHC class II molecules identical to those of NZB/W) MCs were used. Monocyte chemoattractant protein-1 (MCP-1) and osteopontin (OPN) expressions either in the baseline (normal culture) condition or in the presence of LPS were evaluated by real-time PCR, ELISA, or western blot analysis. NF-κB was detected by ELISA, electrophoresis mobility-shift assay, and immunofluorescence. First, either in the baseline condition or in the presence of LPS, NZB/W MCs produced significantly higher levels of MCP-1 and OPN than the DBA/W MC controls. Second, NZB/W MCs expressed significantly higher levels of Toll-like receptor 4, myeloid differentiation factor 88, and NF-κB than the DBA/W MC controls, both receiving exactly the same LPS treatment. In conclusion, NZB/W MCs are significantly more sensitive than their normal control DBA/W MCs in producing both MCP-1 and OPN. With LPS treatment, the significantly elevated levels of both chemokines produced by NZB/W MCs are more likely due to a significantly greater activation of the Toll-like receptor 4-myeloid differentiation factor 88-associated NF-κB pathway. The observed abnormal molecular events provide an intrarenal pathogenic pathway involved in an accelerated type of LN, which is potentially infection triggered

    Therapeutic effects of Jiaotai pill on rat insomnia via regulation of GABA signal pathway

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    Purpose: To investigate the therapeutic effects of Jiaotai pill (JTP) on rats with insomnia induced by pchlorophenylalanine (PCPA).Methods: Rats with PCPA-induced insomnia were divided into 5 groups (n = 10), made up of control group, positive treatment group (estazolam 0.1 mg/kg), and 3 JTP treatment groups (0.6, 1.2 and 2.4 g/kg). Another group of 10 rats were treated as normal group. Rats in normal and control groups were treated with normal saline (10 mL/kg). After 14 days of drug treatment, the rats were injected intraperitoneally with sodium pentobarbital (45 mg/kg) and thereafter, latent period and sleeping time were recorded, while contents of γ-aminobutyric acid (GABA) and glutamic acid (Glu) in hypothalamus were determined by high performance liquid chromatography (HPLC). Furthermore, the expressions of glutamate decarboxylase 65 (GAD-65), glutamate decarboxylase 67 (GAD-67), GABAaminotransferase (GABA)-T, anti-GABA transporter 1 (GAT)-1, anti-GABA transporter (GAT)-3, and GABA receptors (GABA-A and GABA-B) in the hypothalamus were analyzed by western blotting assay.Results: The results showed that JTP (0.6, 1.2 and 2.4 g/kg) significantly shortened latent period and prolonged sleeping time (p < 0.01). JTP also increased GABA level (p < 0.01), but decreased Glu contents of the rat hypothalamus (p < 0.01). Western blotting data indicate that JTP significantly upregulated the levels of GAD-65 (p < 0.01), GAD-67 (p < 0.05), GAT-1 (p < 0.01), GAT-3 (p < 0.01), GABA-A (p < 0.01) and GABA-B (p < 0.01), while the level of GABA-T was down-regulated.Conclusion: The results demonstrate that JTP possesses significant sedative effects on insomnia in rats, most probably through a mechanism involving GABA signal pathway.Keywords: Jiaotai pill, Insomnia, GABA, Glutamate, Estazolam, GABA signal pathwa
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