Disinfection by Chemical Oxidation Methods

Poor quality in drinking water is primary cause of pathogen transmission and responsible of varied infectious diseases. Methods of water treatment for human consumption must pay special attention on microbiological safe disinfection. Indeed, from the past few years laws all around the world have included new, more stringent water quality parameters. Chlorination and other mainly used conventional disinfection processes usually do not achieve full inactivation of all microorganisms present in real water supplies, whereas the presence of even low concentrations of organic matter can lead to form harmful disinfection by-products. Protozoan parasites Giardia sp. and Cryptosporidium sp. are some of the microorganisms that cannot be completely inactivated via chlorination under the same contact times typical of bacteria or virus elimination. It has increased toxicological and microbiological risks as well as operational costs. Disinfection by the advanced oxidation process more intensively studied in the past few years has been reviewed including Fenton and photo-Fenton processes and photocatalytic and electro-catalytic variants; this vibrant topic still remains partially uncovered in the available scientific background, which has motivated many recent researches and publications. This chapter is then devoted to briefly review the most recent reports studying the disinfecting potential displayed by mentioned AOPs with respect to widely and currently used conventional techniques. Revision of the inactivation of water-borne pathogens including E. coli, total coliforms, parasites as Giardia and Cryptosporidium, and virus such as coliphages has focused on advantages and disadvantages in application of every particular AOP, their disinfecting mechanisms, and the main parameters affecting the disinfection response

The impact of surgical delay on resectability of colorectal cancer: An international prospective cohort study

AimThe SARS-CoV-2 pandemic has provided a unique opportunity to explore the impact of surgical delays on cancer resectability. This study aimed to compare resectability for colorectal cancer patients undergoing delayed versus non-delayed surgery.MethodsThis was an international prospective cohort study of consecutive colorectal cancer patients with a decision for curative surgery (January-April 2020). Surgical delay was defined as an operation taking place more than 4 weeks after treatment decision, in a patient who did not receive neoadjuvant therapy. A subgroup analysis explored the effects of delay in elective patients only. The impact of longer delays was explored in a sensitivity analysis. The primary outcome was complete resection, defined as curative resection with an R0 margin.ResultsOverall, 5453 patients from 304 hospitals in 47 countries were included, of whom 6.6% (358/5453) did not receive their planned operation. Of the 4304 operated patients without neoadjuvant therapy, 40.5% (1744/4304) were delayed beyond 4 weeks. Delayed patients were more likely to be older, men, more comorbid, have higher body mass index and have rectal cancer and early stage disease. Delayed patients had higher unadjusted rates of complete resection (93.7% vs. 91.9%, P = 0.032) and lower rates of emergency surgery (4.5% vs. 22.5%, P ConclusionOne in 15 colorectal cancer patients did not receive their planned operation during the first wave of COVID-19. Surgical delay did not appear to compromise resectability, raising the hypothesis that any reduction in long-term survival attributable to delays is likely to be due to micro-metastatic disease