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Heavy Metals
Published in Abhik Gupta, Heavy Metal and Metalloid Contamination of Surface and Underground Water, 2020
Bismuth (Bi) with an atomic number of 83, an atomic weight of 208.98, and a density of 9.75 g cm–3 is a heavy metal that occurs in nature both as a free metal and in ores. The two major ores are bismutite, which is bismuth subcarbonate [Bi2(CO3)O2], and bismuthinite or bismuth sulfide [(Bi2S3)]. Bismuth in these ores is associated with lead and antimony. The major use of bismuth is in the making of alloys, especially those with low melting points, which are often used in welding. Bismuth telluride is a semiconductor, and several bismuth salts are used in cosmetics and medicines. Bismuth also acts as a catalyst in the production of acrylic fibers, and in fire detectors and extinguishers (Encyclopaedia of Occupational Health and Safety 2012).
Phosphorus in alkaline soils of the semiarid region, Brazil: inorganic fractions, capacity factor, and availability
Published in International Journal of Phytoremediation, 2023
Maria Regilene de Freitas Costa Paiva, Fábio Henrique Tavares de Oliveira, Welka Preston Leite Batista da Costa Alves, Milene de Lima Farias, Marx Lima da Cunha, Hernane Arllen Medeiros Tavares, Helena Maria Morais Neta Góis, Marina Beatriz da Silva Bezerra Santos, Jandeilson Alves de Arruda, Leilson Costa Grangeiro, Marcio Gleybson da Silva Bezerra, Francisco Vanies da Silva Sá
For each battery of samples to be analyzed, a blank test was performed adopting the same procedures as those for the other samples, excluding only the digestion of dry matter. P was quantified in the extracts by colorimetry (Braga and Defelipo 1974). The ion H2PO4− in a strongly acidic medium reacts with molybdate (MoO4−), forming a blue complex, and the intensity of the color is proportional to the concentration of P. For this analysis, ammonium molybdate solution was prepared at 2%, and then 20 g of (NH4+)6. The Mo7O24 (A.R.) was dissolved in 200 mL of water. In another flask with 500 mL of H2O, 2 g of bismuth subcarbonate were dissolved, and 150 mL of 98% H2SO4 (A.R.) were added. Subsequently, the mixture was allowed to cool, and the two solutions were mixed and completed to 1,000 mL with H2O (solution 1). The diluted molybdate solution was prepared by transferring 300 mL from solution 1 to a 1,000-mL flask and completing the volume with H2O (solution 2). For the standard P solution of 1,000 ppm, 4.3928 g of KH2PO4 (A.R.) were transferred to a 1,000-mL flask, then 3 mL of 98% H2SO4 were added and completed with H2O. Then, the standard P solutions were prepared from the 1,000 ppm P solution, with 0, 0.5, 1.0, 2.0, 3.0, and 4.0 ppm of P. Finally, crystalline ascorbic acid (A.R.).
Effectiveness of iodoform-based filling materials in root canal treatment of deciduous teeth: a systematic review and meta-analysis
Published in Biomaterial Investigations in Dentistry, 2022
Manoelito Ferreira Silva Junior, Leticia Maíra Wambier, Mayara Vitorino Gevert, Ana Cláudia Rodrigues Chibinski
Several iodoform-based filling materials had been used in the studies. Iodoform with calcium hydroxide was present in the commercial brands: Metapex [9,10,19,20] and Vitapex [14–17,27–29] and Maisto-Capurro paste [30]. Iodoform associated with zinc oxide, eugenol and calcium hydroxide was synthesized using all these components [17], without addition of chlorophenol [9], with addition of propolis [36], or as the commercial brand (Endoflas) [11,12,18,19,35]. One study used iodoform, zinc oxide and eugenol (RCFill) [16] and another study used iodoform, zinc oxide eugenol (ZOE), bismuth subcarbonate, resins, barium sulphate, eugenol and excipients (Zical) [21]. Two studies used different versions of the modified Guedes-Pinto paste [37,38], and finally one study used Maisto paste [13].
Novel high-strength thromboresistant poly(vinyl alcohol)-based hydrogel for vascular access applications
Published in Journal of Biomaterials Science, Polymer Edition, 2020
Matthew M. Mannarino, Michael Bassett, Daniel T. Donahue, James F. Biggins
PVA-Bismuth Subcarbonate polymer suspension was prepared by combining 42.75 g Bismuth Subcarbonate, 179.25 g of 0.62 w/w% monobasic sodium phosphate solution, and 78.00 g PVA 28-99. Substituents were heated to 80 °C in a sealed polypropylene jar and mixed until fully dissolved. After mixing, the polymer suspension was placed on a tube roller mixer at approximately 60 RPM for to prevent separation as it cooled to room temperature. The polymer suspension was then fed into a C.W. Brabender Advanced Torque Rheometer (ATR) with ¾” single screw extruder attachment. The polymer suspension was heated to 80 °C and extruded through a die into an ethanol bath at 10 ± 2 °C on an acetal core filament. The extruded PVA tubes were cut to approximately 75 cm long segments and soaked in ethanol for a minimum of 3 h at room temperature. The core filaments were then removed by hand and samples were soaked for 16 h at 37 ± 2 °C in a neutralized 1 w/w% PAA solution in phosphate buffered saline (PBS). Samples were then removed from the PAA solution, mounted on PTFE-coated stainless-steel mandrels and dried. Samples were then heat treated at specified temperatures for 1.5 h in a forced air convection oven.