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Introduction
Published in Jubaraj Bikash Baruah, Principles and Advances in Supramolecular Catalysis, 2019
For protective measures of certain insects, they release gases, and the release of gas is very fast, comparable to an explosion at a micro level caused by such insects. An insect named the bombardier beetle, under a panic situation or in apprehension of danger, sprays an irritating substance through a sudden blast from the prostate part of the body (circled in Figure 1.2), which it uses as a biologically built-in weapon. The spray is as hot as 100°C and spreads to a 10–20 cm distance with a velocity of about 10 m/sec. The entire process happens as a result of the ability of the pygidial glands of the beetles to control the reactants of the process. The gland acts as a reservoir to provide (a) a reaction chamber and also (b) the exit path to discharge the products. The reservoir stores an aqueous solution of hydrogen peroxide, 1,4-dihydroxybenzene and alkanes. The reaction chamber contains peroxidase and catalase enzymes that perform catalysis to cause very fast reactions among the reactants. When beetles spray the hot, irritating gas for their self-defence, there is a biological process that transfers the components of the reactants in the reservoir to the enzyme-containing chamber. By this process, a molecule of 1,4-dihydroxybenzene is oxidised to 1,4-benzoquinone and, as a consequence of this oxidation, oxygen also evolves by the decomposition of hydrogen peroxide. The 1,4-benzoquinone molecule being a component of the spray, it is the root cause of the irritation caused by the dispersed spray by the beetle. Whereas the exothermic nature of the reaction releases hot oxygen and provides the heat to the spraying liquid/gas mixture. During these courses of action, water vaporises, pressure builds up and the spray explodes from the exit channel.
Antifouling Properties and Biomedical Applications of Conducting Polymers
Published in Ram K. Gupta, Conducting Polymers, 2022
Trinath Biswal, Dharmendra K. Jena, Prafulla K. Sahoo
It was observed that the antifouling CP has been established itself as a suitable candidate for controlled release of drugs and ions, which are accredited to the tunable charged state of the backbone of the polymeric material. The redox states of the CPs can be modified by the application of varying surface potentials and the ions produced can move out or into the CPs to establish their electrostatic neutrality. Nowadays, antifouling zwitterionic form of PEDOT-based material and hydroquinone-functionalized EDOT (EDOT-HQ) is developed, which is highly effective for biomedical applications. The hydroquinone group is responsible for the immobilization of aminooxy-terminated molecules due to the bonding of oxime ligation, onto it, which can be obtained through oxidizing hydroquinone and forms benzoquinone. The oxime ligation bonding is highly stable under different physiological conditions, which is again cleaned by the application of specific reduction potential. The zwitterionic EDOT-PC and EDOT-HQ were initially co-electropolymerized and form films of poly (EDOT-PC-co-EDOT-HQ). The controlled and regulated way of release and attachment of NIH3T3 cells on the film of this copolymer was obtained. Before coupling with poly(EDOT-HQ-co-EDOT-PC) on the RGD peptide, the film of the polymer exhibits appropriate antifouling properties and prevented attachment of NIH3T3. By the application of adequate oxidation potential on the polymeric material film, hydroquinone is converted into benzoquinone. The RGD peptides along with the terminal amino-oxy group have been successfully conjugated on the film (polymer) with subsequent formation of a strong bond with NIH3T3 cells on the surface of the polymeric material. By application of reduction potential, the NIH3T3 cells were successfully from the films of poly(EDOT-HQ-co-EDOT-PC), due to the breaking of the RGD peptide bond. The phenylboronic acid-functionalized EDOT (EDOT-PBA) in combination with antifouling EDOT-EG3 forms a new novel glycan-stimulated PEDOT-based nanomaterial, which can be utilized for CTCs purification from our blood samples. The 3D Nano Velcro chip of PEDOT offers a more capture efficiency and permits the mild release of CTC cells and that release can able for effective CTC purification for analysis from the purified form of CTCs. Hence, the existence of antifouling moieties and their density is the vitals cause for the smooth and effective release of cells without any damage or injury. The elements of antifouling may not be required for the release of tiny molecules from the CPs [49, 50].
Degradation of phenol in wastewater by cathodic microarc plasma electrolysis
Published in Environmental Technology, 2019
Yifan Zhang, Guijun Liu, Ying Wang, Chanchan Shen, Zhanbin Zhang, Hongzhong Shang, Wenbin Xue
In terms of the above analyses of HPLC and LC-MS, the phenol degradation pathways through CMPE are suggested as shown in Figure 9. The Cl substitutes the hydrogen on benzene ring in the initial time, which is replaced by a hydroxyl immediately. The polyhydroxy intermediate products are easier to be oxidized and cleaved due to their higher activation energy. Hydroquinone and 2-chlorohydroquinone are oxidized to become benzoquinone and 2-Chloro-1,4-benzoquinone, respectively. Then those intermediate products are oxidized to generate the aliphatic carboxylic acids [23,25,28]. Furthermore, the pyrogallol from the ortho-substituted product may be cleaved to form 2-hydroxy-cis,cis-muconate [25]. Then 2-hydroxy-cis,cis-muconate is decomposed to become pyruvate and acetaldehyde ultimately. Thus we infer that the KCl electrolyte plays a key role on phenol degradation by CMPE. In addition to the chemical reaction, the instantaneous high temperatures and pressures in the cathodic microarc plasma envelope around Ti cathode may carbonize the phenol into graphite partly.