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Engineering Considerations for Cleaning and Disinfection in the Food Industry
Published in Dennis R. Heldman, Daryl B. Lund, Cristina M. Sabliov, Handbook of Food Engineering, 2018
Kylee R. Goode, David Phinney, Tony Hasting, Peter Fryer
Fan et al. (2015) used reconstituted skimmed milk powder to coat 15 cm stainless steel pipe lengths (dried at 75°C for 30 min) of either 22.2, 34.9 or 47.6 mm ID used to make up 1.35 m long test lines (made up of these individual pipe sections). The piping arrangement investigated is shown in Figure 15.11. Cleaning fluid was pumped around the main 2" pipework at either 1.58, 2.84 or 3.85 m3 s−1 and 22°C, 45°C or 67°C. The fouling sections were located in the middle and at the ends of each test line. The manifold also had a bypass line. Without any routing valves, the flow in each test line was not equalized and was measured using an ultrasonic flowmeter. The presence of fouling was detected after cleaning using an extraction of the pipe surface and quantification of protein in the extract. The amount of deposit remaining on pipe sections before and after water rinsing was determined using a spectrophotometer (at 562 nm) by comparing to an assay curve conducted for bovine serum albumin (BSA), where absorbance intensity of the purple-blue copper-protein complex can be used to infer µg mL−1. The authors presented water flowrate and temperature effect on cleaning the manifold as a global effect; where an increase in both flow velocity and temperature was seen to decrease the amount of residual film across the whole manifold.
Nanobiosensors: Carbon Nanotubes in Bioelectrochemistry
Published in Tuan Vo-Dinh, Nanotechnology in Biology and Medicine, 2017
Anthony Guiseppi-Elie, Nikhil K. Shukla, Sean Brahim
The combination of SWNTs at the GCE surface created a favorable interface that amplified the current response generated from the protein being subjected to a cycling potential. These results strongly suggest that the nanotubes at the GCE surface serve to effectively increase the active electrode surface area and serve an additional dual function: (i) to act as nanoscopic electrical conduits that penetrate the protein surface to within the tunneling distance of the coordinated Cu(I) active site, thus creating an electronic pathway facilitating enhanced shuttling of electrons into and out of the active site (Figure 19.8) and (ii) to create an electrified interface that promotes adsorption of the blue copper protein in a conformation that results in increased electron transfer rates. The pseudoazurin has a highly favored adsorption onto CNT-modified GCE surfaces when compared to unmodified glassy carbon electrodes.
Enzymes for Prodrug-Activation in Cancer Therapy
Published in Peter Grunwald, Pharmaceutical Biocatalysis, 2020
According to Siegel et al. (2018) the estimated number of new cases of malignant melanoma, a highly aggressive form of skin cancer, is 91,270 (55,150 males and 36,120 females) in the USA alone, with a death rate of 10%. Lowe et al. (2014) found that the incidence of cutaneous melanoma among middle-aged adults in the USA increased over the past 4 decades, which is in agreement with reports from other countries, but that disease-specific mortality has decreased, particularly in the last 10 years probably due among others to earlier detection through educational programs, and more skin cancer screenings. Melanoma is a complex and genomically diverse malignancy that has been reviewed by Lin and Fisher (2017) with respect to understanding of signaling and immune regulation in melanoma and implications for responses to treatment by multiple targeted therapies and immunotherapies that have meanwhile entered the clinic. This kind of cancer that in rare cases also occur in the mouth, intestines, or eye, develops from the melanin-containing so-called melanocytes; the skin pigment protects from UVB radiation (Riley, 2003). Among the different types of melanin the most common one is eumelanin with part of its structure shown in the scheme on the previous page; structural building blocks are among others 5,6-dihydroxyindole (DHI), 5,6-dihydroxyindole-2-carboxylic acid (DHICA), and L-dopamine; the arrows indicate possible sites of polymer growth. According to the Raper-Mason pathway (Mason, 1948) eumelanin formation results from the tyrosine hydroxylase and dopa oxidase activity of tyrosinase, an enzyme containing a pair of antiferromagnetically coupled copper ions in its active site. It is present in plant and animal tissues as well as in bacteria (e.g., Streptomyces sp.). The two Cu ions surrounded by six His residues bind one molecule of atmospheric oxygen, required for catalysis: the intermediate L-dopaquinone is formed during the reaction cycles to L-leukodopachrome and reacts with L-dopaquinone to L-dopachrome which is converted to the two eumelanin structural units DHI and DHICA. Further enzyme-catalyzed oxidation of these dihydroxyindoles gives indolequinones; polymer formation occurs via cross-linking reactions (Solano, 2014). A review of structure-function correlations in tyrosinases belonging to the type-3 copper protein family has been provided by Kanteev et al. (2015).
Phosphoester binding, DNA binding, DNA cleavage and in vitro cytotoxicity studies of simple heteroleptic copper(II) complexes with bidentate ligands
Published in Journal of Coordination Chemistry, 2018
Popuri Sureshbabu, Moumita Mondal, Natarajan Sakthivel, Shahulhameed Sabiah
Copper proteins play important roles in biochemical transformations in living systems [1], mainly involved in dioxygen activation and electron transport where copper shuttles between +1 and +2 oxidation states. Copper(II) complexes exhibit various coordination spheres with different types of ligands and interact with biomolecules such as proteins and nucleic acids [2]. Nucleic acids are often targets for drugs which contain phosphodiester bonds, but these bonds are very stable with t1/2 of DNA up to several million years [3]. However, with the help of nuclease enzymes these bonds get hydrolyzed instantly with Mg2+/Zn2+ cofactors [3g]. This enzymatic function is essential for DNA repair, replication, recombination, and relaxation [3g]. Hence, simple complexes which are prone to bind/hydrolyze/cleave DNA play significant roles in developing new therapeutic agents [4–6]. Therefore, research on artificial nucleases under physiological conditions is a current topic. Especially, copper(II) based metal complexes have received considerable importance due to their low cost and wide range of biological applications [7–13].