China
Africa
Explore chapters and articles related to this topic
Utilization of Fisheries' By-Products for Functional Foods
Published in Se-Kwon Kim, Marine Biochemistry, 2023
Muhamad Darmawan, Nurrahmi Dewi Fajarningsih, Sihono, Hari Eko Irianto
Strong evidence showed that many human diseases such as cancer, cardiovascular, stroke, diabetes, rheumatoid arthritis and dementia are associated with the accumulation of free radicals (Florence, 1995). Antioxidants are molecules that are able to donate an electron to a free radical and neutralize it, hence reducing the free radical damage capacity (Lobo et al., 2010). The potential of fish by-products’ protein hydrolysate as a natural antioxidant has also been highlighted and reported by many studies, such as Lassoued et al. (2015), who reported the high antioxidant activity of the pentapeptides Ala-Val-Gly-Ala-Thr purified from the Raja clavate (thornback ray) skin protease-hydrolyzed FPH. The antioxidant potential of fisheries’ by-product FPH was also reported by other studies, such as by Chi et al. (2015), who purified antioxidant peptides of Phe-Ile-Gly-Pro, Gly-Pro-Gly-Gly-Phe-Ile and Gly-Ser-Gly-Gly-Leu from protein hydrolysates of bluefin leatherjacket (Navodon septentrionalis) heads.
Environmental Performance of Bio-Based Polymer Additives: Thermal Stabilizers and Antioxidants
Published in Moayad N. Khalaf, Michael Olegovich Smirnov, Porteen Kannan, A. K. Haghi, Environmental Technology and Engineering Techniques, 2020
Hussein A. Shnawa, Moayad N. Khalaf
Antioxidant is any substance which when found into polymers at small amounts (less than 2 wt% per polymer weight), significantly leads to protection of the polymers and plastics (and other hydrocarbon materials) against thermal and/or photo-oxidative degradation processes. These materials at least, must delay the oxidation process that occur in thermal or photo conditions or during natural ageing. Some types of these additives come from natural resources such as vitamins and many naturally occurring plants products (phytochemicals), and other types produced chemically by industrial processes. Antioxidants are able to neutralize reactive molecules (free radicals) and reduce oxidative damage by different mechanisms. They attract intense scientific and economic interest in polymer and petrochemical industries, human health, and many food industries.16,17
Polymer Technologies
Published in Ghenadii Korotcenkov, Handbook of Humidity Measurement, 2020
Functional initiators find application in conventional radical polymerization for the synthesis of various polymers. The initiator functionality can be considered by reason of the presence of functional end groups, such as hydroxyl and carboxyl, or azo and perester bonds, which undergo dissociation to the alkyl, alkoxy, or acyloxy radicals under the influence of temperature or irradiation and initiate the polymerization (Moad and Solomon 1995). A free radical is simply a molecule with an unpaired electron. The tendency for this free radical to gain an additional electron in order to form a pair makes it highly reactive so that it breaks the bond on another molecule by stealing an electron. As a result, the formation of two additional molecules with an unpaired election (which are another free radicals) takes place. Free radicals are often created by the division of a molecule (known as an initiator) into two fragments along a single bond. The following diagram in Figure 19.5 shows the formation of a radical from its initiator, in this case benzoyl peroxide.
Can Origanum be a hope for cancer treatment? A review on the potential of Origanum species in preventing and treating cancers
Published in International Journal of Environmental Health Research, 2023
Free radicals and reactive oxygen species (ROS) formed in the human body or taken from the outside (through nutrition, etc.) are among the factors that play an important role in cell damage. These free radicals, which adversely affect the immune system and damage human metabolism, are unstable, high-energy compounds with one or more unpaired electrons in their outer orbitals (Yabalak et al. 2020). Therefore, the increasing amount of free radicals in the human body damages or destroys many biological materials (DNA, protein, carbohydrates, etc.) in metabolism. It has been also reported that free radicals play an important role in the pathogenesis of many conditions such as atherosclerosis, aging, cancer, Alzheimer’s and ischemic heart diseases. The increase in free radicals in the human body and the deficiency of antioxidants, which play an active role in the body’s defence by eliminating the harmful effects of free radicals, cause the diseases mentioned above (Stadtman 1992; Guyton and Kensler 1993; Cerutti 1994; Feig et al. 1994). Thus, antioxidants prevent or minimize the harmful effects of the free radicals (Wettasinghe and Shahidi 1999; Koleva et al. 2002).
Development of photocatalytic self-cleaning textiles using tin oxide and titanium dioxide nanoparticles mixture
Published in The Journal of The Textile Institute, 2023
Oormila M. Pillai, Subramanian Sundaramoorthy
Photocatalysis is the acceleration of a photoreaction in the presence of a catalyst. In photogenerated catalysis, charge separation occurs, that leads to electron-hole pairs thereby creating free radicals in the system for redox of the substrate. The resulting free radicals are very efficient oxidizers of organic materials and can degrade pollutants (Aarthi et al., 2007; Matthews, 1988). The photocatalysis by semiconductor materials have been studied by the researchers Al-Hamdi et al. (2017) and Navidpour et al. (2019). Titanium dioxide is a semiconductor material widely used as photocatalyst and its mechanism of photocatalysis was studied by Norouzi and Maleknia (2010). TiO2 as a photocatalyst exhibits strong oxidative potential and chemically stable properties (Banerjee et al., 2014). The nanocrystalline TiO2 coatings can chemically breakdown adsorbed organic contaminants in the presence of sunlight.
Health risks from multiroute exposure of potentially toxic elements in a coastal community: a probabilistic risk approach in Pangkep Regency, Indonesia
Published in Geomatics, Natural Hazards and Risk, 2022
Ratna Dwi Puji Astuti, Anwar Mallongi, Kyungho Choi, Ridwan Amiruddin, Muhammad Hatta, Kraichat Tantrakarnapa, Annisa Utami Rauf
The 95th percentile value represents the highest exposure that is reasonably predicted to occur at the site and is known as the reasonable maximum exposure (RME) (USEPA 2001). An RME value that exceeds the target level risk or the allowable risk means that implementation of risk reduction measures is needed. Based on the equation by Ditjen (2012), a recommended value for restricting shellfish consumption (EF-SF: 3 days/year for adults and EF-SF: 7 days/year for children) should be put in place to avoid carcinogenic risk. Aside from limiting shellfish consumption, several studies recommend implementing a well-balanced diet to avoid chronic diseases such as cardiometabolic disease and death (Zhai et al. 2015; Micha et al. 2017). A recent review by Zhai et al. (2015) stated that the consumption of vegetables, fruits, and other edible plants containing vitamins and essential metals can reduce the toxicity of metals in the human body. Vitamins C and E are antioxidants that have the benefit of scavenging free radicals and decreasing lipid peroxidation. For the recreational scenario, limiting ED may protect the population from carcinogenic risk with recommended ED values of 13 years (adults) and 9 years (children).