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High-Performance Liquid Chromatography
Published in Adorjan Aszalos, Modern Analysis of Antibiotics, 2020
Joel J. Kirschbaum, Adorjan Aszalos
Cefmenoxime in plasma and urine was quantified using a phenyl column and a mobile phase of acetonitrile-0. 2% phosphoric acid (14:86) flowing at 2 ml/min into a 254 nm detector [228]. Recoveries averaged 99% using p-anisic acid as internal standard. Lower detection limits were 0.2 µg/ml plasma and 5 µg/ml urine. The drug was assayed in plasma modifying this method using an octadecylsilane column with a mobile phase of acetonitrile-0.2 M acetate buffer, pH 5.3, flowing at 2 ml/min into a 254 nm detector [229]. The minimum limit of detection was 0.05 µg/ml using the same internal standard, and linearity of response was found from 0.5 to 200 µg/ml. Recoveries averaged 99%. Another modification exists [230].
ExperimentaL Oral Medicine
Published in Samuel Dreizen, Barnet M. Levy, Handbook of Experimental Stomatology, 2020
Samuel Dreizen, Barnet M. Levy
Burstone98 detailed the histologic changes in oral tissues of mice in response to continuous irradiation. In this study, 30 young adult C57 black mice were injected s.c. with a solution of carrier-free P32. Dosages of 30, 20, and 10 μCi/g of body weight were used. Controls consisted of untreated mice and of mice injected with nonradioactive phosphoric acid in quantities similar to the radioactive preparation. All animals were killed 7 to 10 days after injection. The heads were split longitudinally, fixed in 10% formalin, decalcified, processed, sectioned, and stained with hematoxylin and eosin.
Precipitation and Acid/Base Aqueous Reactions
Published in Patrick E. McMahon, Rosemary F. McMahon, Bohdan B. Khomtchouk, Survival Guide to General Chemistry, 2019
Patrick E. McMahon, Rosemary F. McMahon, Bohdan B. Khomtchouk
Complete the reaction and write all three equation formats for the following partial acid/base reactions. Use the solubility guidelines and refer to Section IV for names, strengths, and properties of acids and bases if necessary. Aqueous nitric acid reacts with insoluble solid magnesium hydroxide.Aqueous phosphoric acid reacts with aqueous strontium hydroxide.Aqueous acetic acid reacts with aqueous ammonia.Aqueous sulfuric acid reacts with aqueous sodium acetate. Acetate is the conjugate base of acetic acid; acetic acid is a weak acid and is aqueous soluble.
Adsorption of water pollutants using H3PO4-activated lignocellulosic agricultural waste: a mini review
Published in Toxin Reviews, 2023
Lawal Sirajo, Muhammad Abbas Ahmad Zaini
Almost all conceivable plant-based materials can be converted into AC by chemical activation using phosphoric acid. Over the last ten years, phosphoric acid has been studied as activator for lignocellulosic materials such as coconut shell (Gratuito et al. 2008; Wilson et al. 2017; Nyamful et al. 2021), olive stone (Yakout and Sharaf El-Deen 2016), maize tassel (Olorundare et al.2014), rice husk (Hossain et al. 2020), avocado seed (Julius 2011), and Chinese herbal medicine waste (Mi et al.2015), to mention but a few. Jagtoyen and Derbyshire (1998) studied H3PO4 activation of different lignocellulosic materials. The AC produced exhibits adsorptive properties suitable for water pollutants removal. The physicochemical properties of AC depend upon the structure and composition of feedstock and operating conditions of activation process (Derbyshire 1994; Heidarinejad et al.2020).
Impact of adhesive application errors on dentin bond strength of resin composite
Published in Biomaterial Investigations in Dentistry, 2022
Benjamin Michael Schärer, Anne Peutzfeldt
Current adhesive systems, which are supposed to eliminate the mentioned difficulties inherent to dentin, can be categorised into two main classes: the etch-and-rinse and the self-etch systems [6,7]. To summarize, in the etch-and-rinse systems first 32–37% phosphoric acid is applied which induces a superficial demineralisation of the dentin, whereby the collagen mesh is exposed [7]. This is followed by the application of a primer and subsequently by the application of an adhesive (three-step etch-and-rinse adhesive systems, e.g. OptiBond FL) or by the application a combined primer and adhesive (two-step etch-and-rinse adhesive system). The collagen mesh exposed by the phosphoric acid is thus infiltrated by monomers present in the primer/adhesive. Today, etch-and-rinse adhesive systems are still considered the gold standard as they are the oldest products on the market and can provide excellent results [8]. Due to the time-consuming and complex application of the etch-and-rinse adhesive systems, there has been a trend towards developing simplified adhesive systems, so-called self-etch adhesive systems [8]. These systems do not require application of phosphoric acid, as they comprise an acidic primer. For all systems however, the formation of the resin composite-dentin bond is the result of superficial dentin demineralisation with subsequent infiltration of resin monomers, which interlock micromechanically in the porosities after the polymerisation [9].
The adverse effects of radiotherapy on the structure of dental hard tissues and longevity of dental restoration
Published in International Journal of Radiation Biology, 2020
Miguel Angel Muñoz, Carolina Garín-Correa, Wilfredo González-Arriagada, Ximena Quintela Davila, Patricio Häberle, Ana Bedran-Russo, Issis Luque-Martínez
In all doses applied in enamel, the ER strategy yielded greater bond strength than the SE-based strategy, due to the well-established mechanical interlocking of the polymerized adhesive in the interprismatic spaces, generated by the etching with phosphoric acid. However, when the microshear test was performed, a high percentage of enamel-cohesive fractures (40.5 to 52.6%) were observed, and only in the irradiated ER groups. Alterations in the organic enamel matrix were observed at 20 Gy doses, which, together with the interprismatic spaces (Madrid et al. 2017) consequent to the ionizing radiation, may have a direct impact on the changed degree of anisotropy reflected in the fracture resistance and reduced ability of the enamel to prevent cracks from spreading (Yahyazadehfar and Arola 2015), as well as in the drastic decrease observed in the microhardness. In addition, in the ER strategy, the application of phosphoric acid has an unspecified action, because it removes minerals and affects the organic content without discrimination, and its interaction with the irradiated enamel has not been clarified. Tabata et al. (2017) attribute to etching, with 40% phosphoric acid, the deterioration of the integrity of the enamel adjacent to the restoration bonded with a two-step self-etching adhesive (pH = 2.1) and the formation of cracks. The superficial interaction and less depth etching of SE may account for the lower percentage of cohesive fractures over weakened enamel, even after ionizing radiation.