Physics of Ultrasound
Marvin C. Ziskin, Peter A. Lewin in Ultrasonic Exposimetry, 2020
Sometimes it is difficult to be certain whether or not cavitation is occurring. A simple direct method is to use the starch test for free iodine when a solution of potassium iodide is irradiated, indicating the production of free radicals. Cavitation-produced free radicals can also convert nonfluorescent terephthalic acid to highly fluorescent hydroxyterephthalate96 which can be assayed by spectrophotometer. Because cavitation is a nonlinear phenomenon, first-order subharmonics of the driving frequency are produced and these can be detected by a suitable hydrophone.97 At low intensities and high frequencies, resonant cavitation bubbles emit second-harmonic pulsations.98 Another method is to look for sonoluminescence, which is discussed in the next section.
Screening Smokes: Applications, Toxicology, Clinical Considerations, and Medical Management *
Brian J. Lukey, James A. Romano, Salem Harry in Chemical Warfare Agents, 2019
Chemistry and generation. Terephthalic acid (TA) smoke is generated pyrotechnically from grenades and smoke pots and is similar in performance to cinnamic acid as a white vaporization/condensation thermally generated smoke. The M83 grenade and the M8 smoke pot were developed by the U.S. Army for training purposes to simulate HC smokes. A typical M83 smoke grenade contains terephthalic acid, sugar, potassium chlorate, magnesium carbonate, stearic acid, and a binder (Anthony et al., 2003). Terephthalic acid is a precursor to polyethylene terephthalate (PET), which is used to manufacture beverage containers and used in some clothing fibers.
Impaired exercise capacity in electrostatic polyester powder paint workers
Published in Inhalation Toxicology, 2021
Ukbe Sirayder, Deniz Inal-Ince, Cihangir Acik, Ferhan Soyuer
Electrostatic powder paints (EPP) contain polyester, which is a hydrocarbon. It is a polymer that is formed by melting at a high temperature of petroleum and produced ‘terephthalic acid’ and ‘ethyl glycol,’ and it is a carcinogenic substance (Pang et al. 2016). Polyester is used in electrostatic paint production due to its electrostatic properties. Polyesters are known to cause various skin diseases (Meyers 2010). In addition, it decreases the progesterone ratio in pregnant women due to its electrostatic effect and causes miscarriage. In male subjects, the use of polyester underwear has been reported to reduce sperm count and quality. The inhalation of polyester, which has serious side effects even in contact with the skin, is hazardous (Dale et al. 2014). When animal experiments conducted to investigate the effectiveness of polyester are examined, it is seen that exposure to polyester causes damage to the lung tissue the most. At 13 weeks, it has been shown to cause an increase in the weight, the number of macrophages and inflammatory cytokines of the affected lung tissue (Katz et al. 1997). In addition to the polyester in powder paints, organic, metallic, and plastic pigments, binders, and thinners are used. Each of these may accumulate in the lungs as a result of inhalation and may cause occupational lung diseases (Meyers 2010).
Improving curcumin bactericidal potential against multi-drug resistant bacteria via its loading in polydopamine coated zinc-based metal–organic frameworks
Published in Drug Delivery, 2023
Abdul Jabbar, Khadija Rehman, Tooba Jabri, Tasmina Kanwal, Samina Perveen, Md Abdur Rashid, Mohsin Kazi, Saeed Ahmad Khan, Salim Saifullah, Muhammad Raza Shah
The CUR loading, PDA coating, and Zn-MOFs synthesis were evaluated by FT-IR analysis. In the FT-IR spectrum of terepthalic acid, an absorption peak at 3250 cm−1 region corresponds to the O-H group and a significant absorption peak was observed at 1660 cm−1 corresponds to the C = O group of carboxylic acid (Figure 5A). The FT-IR spectrum of prepared Zn-MOFs did not exhibit the significant peak of terephthalic acid at 3250 cm−1 because of coordination with zinc. Moreover, after coordination with Zn, a little shift in absorption frequency from 1660 cm−1 to 1652 cm−1 was seen. The FT-IR spectra of CUR exhibited the typical peaks of O-H and C = O at 3520 cm−1 and 1626 cm−1, respectively, clearly demonstrating the interaction of CUR with the produced Zn-MOFs (Figure 5C). After being incorporated in Zn-MOFs, the significant peak of Zn-MOFs was slightly moved to 3450 cm−1 along with decreased intensity. In addition, the presence of CUR in the Zn-MOFs was confirmed by the appearance of the significant peak of C = O of CUR in the loaded Zn-MOFs (Figure 5D). The O-H signal was occurred at 3329 cm−1 in the FTIR spectrum of dopamine, while benzene ring was identified at 1615 cm−1 (Figure 5E). As shown in Figure 5F, the corresponding functional groups were submerged in the surface coating process, as the normal dopamine peak at 3329 cm−1 was disappeared whereas a prominent peak at 3183 cm−1 was found after modification.
De-novo identification of specific exposure biomarkers of the alternative plasticizer di(2-ethylhexyl) terephthalate (DEHTP) after low oral dosage to male volunteers by HPLC-Q-Orbitrap-MS
Published in Biomarkers, 2018
Frederik Lessmann, Daniel Bury, Tobias Weiss, Heiko Hayen, Thomas Brüning, Holger M. Koch
The initial screening experiment 1 had also shown mass signals for five so far unknown metabolites. Signals, however, were less intensive than for the already known metabolites. Thus, we decided to lower the threshold values for this experiment (minimum AGC target 6.4e3, corresponding to an intensity threshold of 1e5), in order to still trigger MS2 scans. All metabolites newly identified by the LC-Q-Orbitrap-MS approach yielded the characteristic fragments m/z 121.0295 and m/z 165.0193. Contrary to LC-QqQ-MS (Lessmann et al. 2016a), the fragment m/z 77.0397 was observed only for some but not all new metabolites which, however, is in agreement with the LC-Q-Orbitrap-MS fragmentation behaviour of the already known metabolites. In the case of the additionally hydroxylated metabolites ((OH)2-MEHTP and OH-cx-MHeTP), fragments derived from the terephthalic acid moiety were present (m/z 121.0295 and m/z 165.0193), whereas fragments expected in case of a hydroxylation at the aromatic ring (m/z 181.0143, m/z 137.0244, m/z 93.0346, and m/z 65.0397) were not. Thus, we reason, that the additional hydroxyl group is located at the alkyl side chain. In case of OH-cx-MHeTP at 8.4 min, this hypothesis was confirmed by the presence of fragment ion masses corresponding to the hydroxylated side chain fragments m/z 157.0871 (either formed by elimination of terephthalic acid or by loss of water at the aliphatic carboxylic acid moiety (in analogy to Grossert et al. (2005)), followed by ester cleavage) and m/z 111.0813 (formed by charge remote fragmentation at the alkyl chain carboxylic acid, eliminating formic acid (Grossert et al. 2005) and elimination of terephthalic acid).
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