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Introduction to Cancer, Conventional Therapies, and Bionano-Based Advanced Anticancer Strategies
Published in D. Sakthi Kumar, Aswathy Ravindran Girija, Bionanotechnology in Cancer, 2023
Overproduced free radicals react with proteins and fatty acids of the cell membrane, impairing their function permanently. Furthermore, the abundance of free radicals can result in DNA damage and mutations that can predispose to cancer and old age-related disorders [60]. Tumor formation due to endogenous free radical reactions may be due to their initiation by ionizing radiation. Oxidative stress ensues following the body’s inability to regulate overwhelming free radicals. Therefore, free radicals can adversely modify proteins, lipids, and DNA, and lead to the formation of a number of diseases. Applying external sources of antioxidants can aid in coping with oxidative stress [61].
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
Computational Fluid Dynamics as a Modern Tool in Studies of Biomass-Based Small-Scale Energy Devices
Published in Mateusz Szubel, Mariusz Filipowicz, Biomass in Small-Scale Energy Applications: Theory and Practice, 2019
Mateusz Szubel, Maciej Kryś, Karolina Papis
According to the simplest definition of combustion, the fuel and the oxidizer react and result in a product. In reality, however, even the simplest reaction includes a series of elementary reactions that result in the presence of some transitional substrates (such as radicals) in the system. The radicals are unstable and very reactive. Usually, the radicals that take part in such processes are H, O, OH, CH, HO2, or C2. To exemplify this, simple hydrogen combustion can be presented as [19]: H2+12O2→H2O.
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).
Effect of Oxygen on Radical Reaction during Oxidation of Different-rank Coals
Published in Combustion Science and Technology, 2023
Xiaoyuan Jiang, Shengqiang Yang, Jiawen Cai, Buzhuang Zhou
If the radical concentration is used directly to judge the spontaneous combustion tendency of coal, it is concluded that anthracite and bitumite are more prone to spontaneous combustion than lignite, which, however, is contrary to our common sense of spontaneous combustion tendency, that is, lignite > bitumite > anthracite. Hence, the radical concentration fails to directly characterize the spontaneous combustion tendency of coal. In fact, radicals in coal fall into two types, namely stable radicals and active radicals (Dai 2012; Zhou et al. 2019). Stable radicals require vast energy to become unstable as a result of space barrier and displacement obstruction, so they have a low reactivity. In contrast, active radicals tend to combine and react with other radicals containing unpaired electrons, so they have a high reactivity (Cai et al. 2021). This means that the radical reaction of coal is determined by the content of active radicals. Therefore, the growth rate of radical concentration is introduced to express the oxidation capacity of coal. Based on the radical concentration of coal at the beginning of oxidation (T0= 50°C), dividing the difference between the radical concentration at the set temperature(Ti) and at the initial temperature (T0= 50°C) by the radical concentration at the initial temperature, the ratio is defined as the growth rate of radical concentration. The formula of the growth rate of radical concentration is:
Impact of adding EDA in Jatropha and waste cooking oil biodiesel on NOx reduction in diesel engine emission
Published in International Journal of Ambient Energy, 2022
Sandeep Gupta, Mahendra Pal Sharma, Devaki Nandan Sharma, Astha Verma
For the biodiesel–diesel blend BSFC is higher (Figure 10) and BTE is lower than diesel (Figure 11). As the biodiesels have lower calorific value, higher density and viscosity compared to pure diesel, which reduces the atomisation of blended fuel, leading to poor mixture formation of fuel with air for the combustion process (Elkelawy et al., 2019; Nalgundwar et al., 2016; Dhar et al., 2014). With the addition of an antioxidant additive, the BSFC increases, and BTE decreases in small amounts because the antioxidant creates a disturbance in the combustion process. During the combustion process, free radicals form near the hydrocarbon flame. The antioxidant additive gives an electron to these free radicals, thereby disturbing the combustion process and consuming more fuel (Balaji et al., 2019).