RESUMO
Cyanotoxins pose a health threat when present in the drinking water supply since conventional water treatment processes are not effective in removing extracellular metabolites hence, advanced treatment techniques are usually applied. Powdered activated carbon (PAC) is an effective adsorbent for removing toxins. However, since a high volume is necessary, alternative adsorbents have been investigated. Biochar, especially from renewable sources, is a potential adsorbent material that could replace PAC for removing toxins. This paper aimed to investigate which PAC properties play key roles in cyanotoxin adsorption by a systematic review addressing the adsorption of toxins such as microcystins-LR (MC-LR), cylindrospermopsin (CYL), and saxitoxins (STXs). As a result, the review showed that some commonly adopted indices (i.e. total surface area) are not relevant to cyanotoxin adsorption, especially if appraised alone. Along with a multi-barrier approach, PAC has to be applied taking into account the complexity of the water system, which includes a better understanding of the characteristics of the adsorbent, the target toxin, and the aqueous medium. The biochar systematic review showed that no studies have yet been designed specifically for the removal of toxins. Since biochar has not yet been applied to water treatment processes, the knowledge gap is even greater than for PAC.
Assuntos
Carvão Vegetal , Toxinas de Cianobactérias , Adsorção , Conhecimento , PósRESUMO
AIMS: While the atherosclerotic plaque volume can be manually quantified in coronary computed tomography angiography (CTA) it is impractical for clinical routine use. Several anatomical scores have been developed as surrogates for overall atherosclerotic burden in coronary CTA and even proven to be highly predictive for future adverse events. However, they have not been validated against the gold standard for atherosclerotic burden, intra-vascular ultrasound (IVUS). In the present study we have compared several coronary CTA scores with the coronary IVUS. METHODS AND RESULTS: A total of 62 patients with diagnosed coronary disease scheduled for percutaneous intervention were prospectively enrolled. For all patients, coronary CTA and multivessel IVUS were obtained. Calcium score and 6 previously reported scores were calculated from coronary CTA imaging and compared to average IVUS-derived percent atheroma volume (PAV). On average, 3.8 ± 0.7 vessels, comprising 123.8 ± 31.3 mm in length, were imaged with IVUS per patient. All but one previously described scoring systems showed a significant association with IVUS-derived PAV. Among them, the SSS score demonstrated the strongest correlation with IVUS-PAV (r = 0.61, p < 0.001) and the greatest area under the ROC curve (C-statistic = 0.87), to predict a high PAV. CONCLUSIONS: Most frequently used coronary CTA scores have a good correlation with global coronary atherosclerotic burden measured by multivessel IVUS derived atheroma volume. Among them, the SSS score shows the best performance being a good non-invasive alternative to IVUS for global coronary atherosclerotic burden assessment.