Bio-Ceramics for Tissue Engineering
Naznin Sultana, Sanchita Bandyopadhyay-Ghosh, Chin Fhong Soon in Tissue Engineering Strategies for Organ Regeneration, 2020
There are several types of bioactive glasses (BG) and these include silicate based-glasses, phosphate based-glasses and borate based – glasses (Jones 2015, Rahaman et al. 2011). Miguez-Pacheco et al. (2015) listed (Table 8.3) the formulations of several bioactive glasses (BG) which have been recently studied and investigated thoroughly (Jones 2015, Rahaman et al. 2011, Nandi et al. 2011, Hench 1998, Brink et al. 1997, Brown et al. 2008, Lindfors et al. 2010, Clare 2004, Detsch et al. 2014, Filgueiras et al. 1993). It can be seen that bioactive silicate-based glasses have been found to be a revolutionary material after trials, showing effective and successful adherence and bonding to human bone and tissue. Hench et al. (Hench et al. 1971, Hench 2006, 2015) designed Bioglass 45S5 with 45 wt. % silica (SiO2), 24.5 wt. % calcium oxide (CaO), 24.5 wt. % sodium oxide (Na2O) and 6 wt. % phosphorus pentoxide (P2O5) as shown in Fig. 8.8. These chemical combinations are categorized as Class A bioactivity owing to their outstanding osteoconductive and osteoproductive characteristics (Hench 2015). This is due to the ions released from BG reacted positively in biological solutions such as in simulated body fluid (SBF) and thus induced the formation of carbonated hydroxyapatite (HCA) layers on the surface of glass (Rezwan et al. 2006, Hoppe et al. 2011).
Writing Chemical Equations
Patrick E. McMahon, Rosemary F. McMahon, Bohdan B. Khomtchouk in Survival Guide to General Chemistry, 2019
Write balanced equations based on the following descriptions: Sulfur dioxide gas reacts with oxygen gas to form sulfur trioxide gas.Calcium oxide solid plus water forms calcium hydroxide solid.Calcium carbonate solid decomposes to form calcium oxide solid plus carbon dioxide gas.Chromium (II) oxide solid is converted to chromium metal plus oxygen gas.Cobalt (II) nitrate in an aqueous solution plus sodium phosphate in an aqueous solution forms cobalt (II) phosphate solid plus sodium nitrate in an aqueous solution.Gold (III) chloride solid reacts with iron metal to form gold metal plus iron (III) chloride solid.Aluminum hydroxide solid decomposes to form aluminum oxide solid plus water.Lead (II) acetate in an aqueous solution reacts with potassium sulfate in an aqueous solution to form lead (II) sulfate solid plus potassium acetate in an aqueous solution.
Miscellaneous Applications
Vlado Valković in Low Energy Particle Accelerator-Based Technologies and Their Applications, 2022
Mortar contains carbon from carbon dioxide absorbed from the atmosphere at the time of construction, which in principle makes it ideal for 14C dating. To produce lime, limestone (fossil calcium carbonate) is heated to above 1000 °C to liberate carbon dioxide and produce quicklime (calcium oxide). The quicklime is then slaked with water to form calcium hydroxide which is mixed with water and sand to form mortar. Calcium hydroxide in mortar reacts with carbon dioxide from the air forming calcium carbonate, hardening the mortar. The 14C content of a mortar sample can thus give a measure of the time elapsed since the time of hardening. As the carbon in the mortar originates from atmospheric carbon dioxide the radiocarbon age arrived at can be converted to calendar years using normal calibration procedures.
Distribution and accumulation of heavy metals in Lake Manzala, Egypt
Published in Egyptian Journal of Basic and Applied Sciences, 2021
The study was carried out on Lake Manzala through summer, 2019, to monitor and evaluate the levels of some heavy metals and major oxides in water and sediments. Ten samples of both water and superficial bottom sediments have been collected. The sample sites have been chosen to cover sources of pollution near to discharges of most drains which consider the main source of pollution of the study area. Every one of the safeguards happened to limit dangers of the test tainting were followed during the assortment and treatment of tests. These samples have been chemically analyzed for the determination of their major oxides (Silica oxide SiO2, Aluminum oxide Al2O3, Ferric oxide Fe2O3, Magnesium oxide MgO, Calcium oxide CaO, Sodium oxide Na2O and Potassium oxide K2O) and a few heavy metals (Cu, Zn, and Pb, Fe, Mn and Cd). The study used the standard of the American Public Health Association (APHA) [11] for the collection, preservation and digestion technique. Heavy metals concentrations were measured using a graphite furnace atomic absorption spectrometer (Buck Scientific Company, USA) after the digestion technique. Calibration standards and quality control samples have been prepared freshly daily. The reference standard materials used to assess the precision and accuracy of the procedure. The study used analytical grade chemicals of certified standard solutions for the aim of sample preparation and its analysis.
Mortality and physiological impacts of the tea saponin against Ephestia kuehniella Zeller (Lepidoptera: Pyralidae)
Published in Toxin Reviews, 2022
Morteza Shahriari, Arash Zibaee, Seyyedeh Kimia Mirhaghparast, Sarah Aghaeepour Pour, Samar Ramzi, Hassan Hoda
Tea saponin was extracted based on the procedure of Li et al. (2012). C. sinensis seeds were collected from Langroud tea gardens (Guilan Province, Northern Iran), powdered, and sifted. The powder was stirred in warm water (liquid to the solid ratio: 6:1; the water temperature: 80 °C; soaking time 6 h). Then, the samples were centrifuged at 5000 rpm, for 30 min at 25 °C to obtain the primary extracted solution. The concentration of 30% of flocculant of polyaluminum chloride was added into the content of 1% of the primary extracted liquid by weight and kept at 25 °C for 2 h to remove impurities. Afterward, centrifugation was performed at 5000 rpm, at 25 °C for 30 min to get the demanded supernatant. Ten grams of calcium oxide as the settlement agent was added to the earlier supernatant and stirred for 4 h before being centrifuged at 5000 rpm for 30 min at 25 °C. The present supernatant was removed, and ammonium bicarbonate was added (30% of the total mixture) to remove calcium from the TS. The samples stirring for 2 h at 60 °C and centrifugated at 5000 rpm for 30 min at 25 °C. Afterward, tubes containing the samples were put in a boiling water bath for 5 min and incubated at 80 °C for 12 h within an oven to gain TS powder (75% purity).
Toxic metals in cement induced hematological and DNA damage as well as carcinogenesis in occupationally-Exposed block-factory workers in Lagos, Nigeria
Published in Egyptian Journal of Basic and Applied Sciences, 2022
Tajudeen Yahaya, Esther Oladele, Titilola Salisu, Esther Orji, Zafira Zakari, Umar Usman Liman, Clement Boniface Gomo, Mustapha Abdullahi
Table 1 shows the demographic characteristics of block factory workers and the control group, which comprises people who did not work in block factories. There was no significant difference (p ≥ 0.05) between the workers and the control group with regards to age, weight, height, and body mass index (BMI). However, while the skin texture of the control group was apparently normal, the workers showed varied skin textures between normal and dry. Toxic metals in cement and sand used in block molding could be the cause of the skin problem. When cement is mixed with water, the calcium oxide in it is converted to calcium hydroxide, which raises the pH of cement to alkalis [19]. The average pH of human skin is 4.7 [20], so the alkaline pH of cement allows it to penetrate the skin and burn it [21]. Chemicals in wet cement may also react with sweat and water molecules in the skin and release free radicals that dissolve proteins and collagen fibers, break down fats, and dehydrate cells [19]. Moreover, hexavalent chromium (present in cement) can cause allergic reactions, resulting in skin conditions ranging from mild rashes to severe skin ulcers. Exposure to silica (present in cement and sand) can also cause a skin condition known as scleroderma [22]. The longer wet cement stays on the skin, the more it reacts with water molecules and the worse the burn becomes [19]. This explains the varied skin conditions of the workers in the current study. The varied skin conditions of the workers could have also been influenced by the level of compliance with the use of protective wear. In the study by [23], skin conditions were common among workers who had worked for more than a year, those who worked longer hours, and those who failed to use personal protective equipment. The results of the current study are consistent with all the retrieved documented studies on the same subject. Notably [23],,reported severe skin conditions among construction workers in India [24].,also noticed skin problems among construction workers in Tanzania [25].,reported skin burns among construction workers exposed to wet cement in Port Harcourt, Nigeria. Pieces or particles of wet blocks can come into contact with the skin if the worker fails to wear protective gear. Wet blocks may also fall inside the boots or gloves of workers or be absorbed through protective clothing.
Related Knowledge Centers
- Alkali
- Calcium
- Chemical Compound
- Corrosion
- Hydroxide
- Inorganic Compound
- Oxide
- Oxygen
- Chemical Formula
- Silicon