Corrosion of a drilling pipe steel in an environment containing sulphate-reducing bacteria

In this study, the microbiologically influenced corrosion caused by sulphate-reducing bacteria (SRB) has been studied. The material tested was a drilling pipe steel designated as N-80. Weight loss studies and potential measurements were carried out in two types of culturing solutions, with and without SRB inoculated. From weight loss studies, corrosion rate in SRB inoculated solution has been found to be roughly six fold greater than that in the medium without SRB. Also under the investigated conditions, the effective concentration of biocide necessary to control corrosion of N-80 steel in the presence of SRB, has been found to be at least 500 ppm. (C) 1997 Elsevier Science Ltd

Effect of salinity on cell growth and β-carotene production in Dunaliella sp. isolates from Urmia Lake in northwest of Iran

Urmia Lake, the second largest hyper-saline lake by area in the world, has fluctuated in salinity over time, but recently, it has reached a maximum of 360 g/l. Dunaliella is a type of halophile green-orange microalgae especially found in lake and salty fields and is known for its antioxidant activity; because of its ability to create large amount of carotenoids. In the present study, Dunaliella sp. isolates from hypersaline Urmia Lake water were cultured in modified Johnson media and were treated at different salinities (1, 2 and 3 M NaCl), then their cell proliferation rate and β-carotene production were studied. In order to determine the optimal salinity required for the highest β-carotene accumulation, cell count of Dunaliella sp. isolates; total carotenoids and concentration of the β-carotene were determined by direct microscopic counting and spectrophotometry. In the samples with different salinities, the cell count and the β-carotene content of Dunaliella sp. ranged between 0.53 and 2.21x106 cell.ml-1 and 0.2 to 11.4 pg.cell-1, respectively. At the end of the experiments, the maximum cell content mean and the highest β- carotene content mean were obtained at 1 and 3 M NaCl concentrations, as 1.68 x 106 cell.ml-1 and 8.94 pg.cell-1, respectively.Keywords: Dunaliella, microalgae, Urmia Lake, chlorophyceae, β-carotene

Dependence of Electrical Resistivity on Temperature and Sn Content in Pb-Sn Solders

WOS: 000287861900012Pb(100-x)-Sn-x solders (x = 5 wt.%, 10 wt.%, 20 wt.%, 35 wt.%, 50 wt.%, 60 wt.%, 61.9 wt.%, and 95 wt.%) were directionally solidified upward with a constant growth rate (V = 37.4 mu m/s) in a temperature gradient (G = 4.8 K/mm) in a Bridgman-type growth apparatus. The variations of electrical resistivity (rho) with temperature in the range of 323 K to 423 K for the directionally solidified Pb-Sn solders were measured. The present measurements indicate that the electrical resistivity of the directionally solidified Pb-Sn solders increases with increasing temperature, whereas the resistivity of the Pb-Sn solders decreases with increasing Sn content. The dependency of the Lorenz number (L) on temperature and Sn content for the Pb-Sn solders was also investigated based on the Wiedemann-Franz law by using the measured values of the thermal (K) and electrical (sigma) conductivity for the same alloys.Nigde University Scientific Research Project Unit [FEB 2008/12]This project was supported by Nigde University Scientific Research Project Unit under Contract No. FEB 2008/12. The authors are grateful to Nigde University Scientific Research Project Unit for their financial support

Dependency of the thermal and electrical conductivity on the temperature and composition of Cu in the Al based Al-Cu alloys

WOS: 000282242200055The variations of thermal conductivity with temperature for Al-[x] wt.% Cu, x = 3, 6, 15 and 24 alloys were measured by using a radial heat flow apparatus. The variations of electrical conductivity of solid phases versus temperature for the same alloys were determined from the Wiedemann-Franz and Smith-Palmer equations by using the measured values of thermal conductivity. From the graphs of thermal and electrical conductivity versus temperature, the thermal conductivity of the solid phases at their melting temperatures, and the thermal temperature and the electrical coefficients for the same alloys were obtained. Dependency of the thermal and electrical conductivity on the composition of Cu in the Al based Al-Cu alloys were also investigated. According to present experimental results, the thermal and electrical conductivity of Al-[x] wt.% Cu, x = 3, 6, 15 and 24 alloys linearly decrease with increasing the temperature and composition of Cu. The enthalpy of fusion and the specific heat change during the transformation for the same alloys were determined from cooling trace during the transformation from eutectic liquid to eutectic solid by means of differential scanning calorimeter (DSC). (c) 2010 Elsevier Inc. All rights reserved.Nigde University Scientific Research Project Unit [FEB 2008/12]This project was supported by the Nigde University Scientific Research Project Unit under Contract No: FEB 2008/12. Authors would like to thank to the Nigde University Scientific Research Project Unit for their financial support

Determination of Interfacial Energies for Solid Al Solution in Equilibrium with Al-Cu-Ag Liquid

WOS: 000277712900008The equilibrated grain boundary groove shapes of a solid Al solution in equilibrium with Al-Cu-Ag liquid were observed from a quenched sample using a radial heat flow apparatus. The Gibbs-Thomson coefficient, solid-liquid interfacial energy, and grain boundary energy of the solid Al solution were determined from the observed grain boundary groove shapes. The thermal conductivity of the solid phase for Al-16.42 at.% Ag-4.97 at.% Cu and Al-16.57 at.% Ag-11.87 at.% Cu alloys and the thermal conductivity ratio of the liquid phase to the solid phase for Al-16.57 at.% Ag-11.87 at.% Cu alloy at the melting temperature were also measured with a radial heat flow apparatus and a Bridgman-type growth apparatus, respectively.Scientific and Technical Research Council of Turkey (TUBITAK) [105T481]This research was financially supported by the Scientific and Technical Research Council of Turkey (TUBITAK under Contract No: 105T481). The authors are grateful to the Scientific and Technical Research Council of Turkey (TUBITAK) for their generous financial support

Thermal conductivity and interfacial energies of solid Sn in the Sn-Cu alloy

WOS: 000273051800027The equilibrated grain boundary groove shapes of solid Sn in equilibrium with the Sn-Cu eutectic liquid were observed from a quenched sample. The Gibbs-Thomson coefficient, solid-liquid interfacial energy and grain boundary energy of solid Sn have been determined to be (8.7 +/- 0.6) x 10(-8) Km, (113.1 +/- 13.6) x 10(-3) J m(-2) and (222.4 +/- 28.9) x 10(-3) J m(-2), respectively. The thermal conductivity of solid phase and the thermal conductivity ratio of liquid phase to solid phase for Sn-1.3 at.%Cu alloy have also been measured with radial heat flow apparatus and Bridgman type growth apparatus, respectively. (C) 2009 Elsevier B. V. All rights reserved.Scientific and Technical Research Council of Turkey (TUBITAK) [107T095]This research was financially supported by the Scientific and Technical Research Council of Turkey (TUBITAK under Contract No: 107T095). Authors are grateful to the Scientific and Technical Research Council of Turkey (TUBITAK) for their financial supports

Tuberculous meningitis in adults - experience from Turkey

Background: The annual incidence of tuberculous meningitis (TM) is unknown. TM is a disease that still often results in residual sequelae, and has a mortality rate ranging between 15 and 51%. Experience of countries such as Turkey where drug-resistant tuberculosis and TM are prevalent is important

Development of Small Molecule MEIS Inhibitors that modulate HSC activity

Meis1, which belongs to TALE-type class of homeobox gene family, appeared as one of the key regulators of hematopoietic stem cell (HSC) self-renewal and a potential therapeutical target. However, small molecule inhibitors of MEIS1 remained unknown. This led us to develop inhibitors of MEIS1 that could modulate HSC activity. To this end, we have established a library of relevant homeobox family inhibitors and developed a high-throughput in silico screening strategy against homeodomain of MEIS proteins using the AutoDock Vina and PaDEL-ADV platform. We have screened over a million druggable small molecules in silico and selected putative MEIS inhibitors (MEISi) with no predicted cytotoxicity or cardiotoxicity. This was followed by in vitro validation of putative MEIS inhibitors using MEIS dependent luciferase reporter assays and analysis in the ex vivo HSC assays. We have shown that small molecules named MEISi-1 and MEISi-2 significantly inhibit MEIS-luciferase reporters in vitro and induce murine (LSKCD34(l)degrees (w) cells) and human (CD34(+), CD133(+), and ALDH(hi) cells) HSC self-renewal ex vivo. In addition, inhibition of MEIS proteins results in downregulation of Meis1 and MEIS1 target gene expression including Hif-1 alpha, Hif-2 alpha and HSC quiescence modulators. MEIS inhibitors are effective in vivo as evident by induced HSC content in the murine bone marrow and downregulation of expression of MEIS target genes. These studies warrant identification of first-in-class MEIS inhibitors as potential pharmaceuticals to be utilized in modulation of HSC activity and bone marrow transplantation studies