Chemical composition and minerals in pyrite ash of an abandoned sulphuric acid production plant

The extraction of sulphur produces a hematite-rich waste, known as roasted pyrite ash, which contains significant amounts of environmentally sensitive elements in variable concentrations and modes of occurrence. Whilst the mineralogy of roasted pyrite ash associated with iron or copper mining has been studied, as this is the main source of sulphur worldwide, the mineralogy, and more importantly, the characterization of submicron, ultrafine and nanoparticles, in coal-derived roasted pyrite ash remain to be resolved. In this work we provide essential data on the chemical composition and nanomineralogical assemblage of roasted pyrite ash. XRD, HR-TEM and FE-SEM were used to identify a large variety of minerals of anthropogenic origin. These phases result from highly complex chemical reactions occurring during the processing of coal pyrite of southern Brazil for sulphur extraction and further manufacture of sulphuric acid. Iron-rich submicron, ultrafine and nanoparticles within the ash may contain high proportions of toxic elements such as As, Se, U, among others. A number of elements, such as As, Cr, Cu, Co, La, Mn, Ni, Pb, Sb, Se, Sr, Ti, Zn, and Zr, were found to be present in individual nanoparticles and submicron, ultrafine and nanominerals (e.g. oxides, sulphates, clays) in concentrations of up to 5%. The study of nanominerals in roasted pyrite ash from coal rejects is important to develop an understanding on the nature of this by-product, and to assess the interaction between emitted nanominerals, ultra-fine particles, and atmospheric gases, rain or body fluids, and thus to evaluate the environmental and health impacts of pyrite ash materials

Charge and mass effects on the evaporation of higher-dimensional rotating black holes

To study the dynamics of discharge of a brane black hole in TeV gravity scenarios, we obtain the approximate electromagnetic field due to the charged black hole, by solving Maxwell's equations perturbatively on the brane. In addition, arguments are given for brane metric corrections due to backreaction. We couple brane scalar and brane fermion fields with non-zero mass and charge to the background, and study the Hawking radiation process using well known low energy approximations as well as a WKB approximation in the high energy limit. We argue that contrary to common claims, the initial evaporation is not dominated by fast Schwinger discharge.Comment: Published version. Minor typos corrected. 29 pages, 5 figure

Hydroxocobalamin Quantification In Human Plasma By High-performance Liquid Chromatography Coupled With Electrospray Tandem Mass Spectrometry In A Pharmacokinetic Study

A rapid, sensitive and specific method for quantifying hydroxocobalamin in human plasma using paracetamol as the internal standard (IS) is described. The analyte and the IS were extracted from plasma by liquid-liquid extraction using an organic solvent (ethanol 100%; -20°C). The extracts were analyzed by high performance liquid chromatography coupled with electrospray tandem mass spectrometry (HPLC-MS-MS). Chromatography was performed on Prevail C8 3 μm, analytical column (2.1×100 mm i.d.). The method had a chromatographic run time of 3.4 min and a linear calibration curve over the range 5-400 ng.mL -1 (r>0.9983). The limit of quantification was 5 ng.mL-1. The method was also validated without the use of the internal standard. The precision in the intra-batch validation with IS was 9.6%, 8.9%, 1.0% and 2.8% whereas without IS was 9.2%, 8.2%, 1.8% and 1.5% for 5, 15, 80 and 320 ng/mL, respectively. The accuracy in intra-batch validation with IS was 108.9%, 99.9%, 98.9% and 99.0% whereas without IS was 101.1%, 99.3%, 97.5% and 92.5% for 5, 15, 80 and 320 ng/mL, respectively. The precision in the inter-batch validation with IS was 9.4%, 6.9%, 4.6% and 5.5% whereas without IS was 10.9%, 6.4%, 5.0% and 6.2% for 5, 15, 80 and 320 ng/mL, respectively. The accuracy in inter-batch validation with IS was 101.9%, 104.1%, 103.2% and 99.7% whereas without IS was 94.4%, 101.2%, 101.6% and 96.0% for 5, 15, 80 and 320 ng/ mL, respectively. This HPLC-MS-MS procedure was used to assess the pharmacokinetics of cobalamin following intramuscular injection 5000 μg in healthy volunteers of both sexes (10 males and 10 females). The volunteers had the following clinical characteristics (according to gender and expressed as mean ± SD [range]): males: age: 32.40 ± 8.00 [23.00-46.00], height: 1.73 ± 0.07 m [1.62-1.85], body weight: 72.48 ± 10.22 [60.20-88.00]; females: age: 28.60 ± 9.54 [18.00-44.00], height: 1.60 ± 0.05 [1.54-1.70], body weight: 58.64 ± 6.09 [51.70-66.70]. The following pharmacokinetic parameters were obtained from the hydroxocobalamin plasma concentration vs. time curves: AUC last, T1/2, Tmax, Vd, Cl, C max and Clast. The pharmacokinetic parameters were 120 (± 25) ng.mL -1 for C max, 2044 (± 641) ng.hr.mL -1 for AUClast, 8 (± 3.2) ng.mL -1 for Clast, 38 (± 15.8) hr for T 1/2 and 2.5 (range 1-6) hr for Tmax. Female volunteers presented significant (p=0.0136) lower AUC (1706 ± 704) ng.hr.mL-1) and larger (p=0.0205) clearance (2.91 ± 1.41 L/hr), as compared to male 2383 ± 343 ng.hr.mL -1 and 1.76 ± 0.23 L/hr, respectively. These pharmacokinetic differences could explain the higher prevalence of vitamin B12 deficiency in female patients. The method described validated well without the use of the internal standard and this approach should be investigated in other HPLC-MS-MS methods. © 2013 Mendes GD, et al.528087Butler, C.C., Vidal-Alaball, J., Cannings-John, R., McCaddon, A., Hood, K., Oral vitamin B12 versus intramuscular vitamin B12 for vitamin B12 deficiency: A systematic review of randomized controlled trials (2006) Fam Pract, 23, pp. 279-285Kuzminski, A.M., Del Giacco, E.J., Allen, R.H., Stabler, S.P., Lindenbaum, J., (1998) Blood, 92, p. 1191van Asselt, D.Z., Merkus, F.W., Russel, F.G., Hoefnagels, W.H., Nasal absorption of hydroxocobalamin in healthy elderly adults (1998) Br J Clin Pharmacol, 45, pp. 83-86Van den Berg, M.P., Merkus, P., Romeijn, S.G., Verhoef, J.C., Merkus, F.W., Hydroxocobalamin uptake into the cerebrospinal fluid after nasal and intravenous delivery in rats and humans (2003) J Drug Target, 11, pp. 325-331Merkus, P., Guchelaar, H.J., Bosch, D.A., Merkus, F.W., (2003) Neurology, 6, p. 1669Chen, J.H., Jiang, S.J., Determination of cobalamin in nutritive supplements and chlorella foods by capillary electrophoresis-inductively coupled plasma mass spectrometry (2008) J Agric Food Chem, 56, pp. 1210-1215Kelly, R.J., Gruner, T.M., Sykes, A.R., Development of a method for the separation of corrinoids in ovine tissues by HPLC (2005) Biomed Chromatogr, 19, pp. 329-333Rosin, H., Man, W.Y., Doyle, E., Bult, A., Beijnen, J.H., (2000) J Liq Chromatogr and Related Tech, 23, p. 329Wang, Y.H., Yan, F., Zhang, W.B., Ye, G., Zheng, Y.Y., (2009) Neurosci Bull, 25, p. 209Dubois, D., Dubois, E.F., (1916) Arch Intern Med, 17, p. 862Mendes, F.D., Chen, L.S., Borges, A., Babadópulos, T., Ilha, J.O., Ciprofibrate quantification in human plasma by high-performance liquid chromatography coupled with electrospray tandem mass spectrometry for pharmacokinetic studies (2011) J Chromatogr B Analyt Technol Biomed Life Sci, 879, pp. 2361-2368Uhl, W., Nolting, A., Gallemann, D., Hecht, S., Kovar, A., Changes in blood pressure after administration of hydroxocobalamin: Relationship to changes in plasma cobalamins-(III) concentrations in healthy volunteers (2008) Clin Toxicol, 46, pp. 551-559. , (Phila