Efficient removal of hexavalent chromium from aqueous solutions using autohydrolyzed Scots Pine ( Pinus Sylvestris ) sawdust as adsorbent

In this work, a low-cost lignocellulosic adsorbent with high biosorption capacity is proposed, suitable for the efficient removal of hexavalent chromium from water and wastewater media. The adsorbent was produced by autohydrolyzing Scots Pine ( Pinus Sylvestris ) sawdust. The effect of the autohydrolysis conditions, i.e., pretreatment time and temperature, on hexavalent chromium biosorption was investigated using energy-dispersive X-ray spectroscopy (EDS) and UV-visible spectrophotometry. The Freundlich, Langmuir, Sips, Radke-Prausnitz, Modified Radke-Prausnitz, Tóth, UNILAN, Temkin and Dubinin- Radushkevich adsorption capacities and the rate constant values for pseudo-first- and pseudo-second-order kinetics indicated that the autohydrolyzed material exhibits significantly enhanced hexavalent chromium adsorption properties comparing with the untreated sawdust. The Freundlich's adsorption capacity KF increased from 2.276 to 8.928 (mg g-1)(L mg-1)1/n, and the amount of hexavalent chromium adsorbed at saturation (Langmuir constant qm ) increased from 87.4 to 345.9 mg g-1 , indicating that autohydrolysis treatment at 240°C for 50 min optimizes the adsorption behavior of the lignocellulosic material

Computational and experimental biomonitoring transboundary pollution for optimizing industrial effluent parameters

This paper deals with monitoring transboundary pollution affecting a waterbody shared by two neighboring countries. The case under examination refers to a river crossing the borders between an upstream and a downstream country (UC and DC, respectively, by considering the borders as reference point), where the source of pollution is located in the UC but the downstream environmental impacts are manifested also in the DC. A methodology is presented, under the form of an algorithmic procedure including 20 activity stages and 10 decision nodes, for quantifying environmental impact, formulating the necessary knowledge framework for maximizing joint benefit and creating the suitable background for bilateral negotiations in order to reach a satisfactory agreement for both parts. The measure of pollution we introduce is the spatio-temporal oxygen deficit given as the area between a critical dissolved oxygen value and the corresponding oxygen sag curve. Based on this measure, we have determined the basic regimes that may appear in practice and we have highlighted the limiting cases that structure the domain where a quasi-optimal solution may be found. It is worthwhile noting that the presented approach can be extended to include water quality issues, especially suitable for dealing with extreme climatic changes (drought, flood, or other impacts of global warming), as well as the introduction of new technologies for improving water utility. © 2009 American Institute of Physics

Prevalence and mechanisms of resistance to fluoroquinolones in Pseudomonas aeruginosa and Escherichia coli isolates recovered from dogs suffering from otitis in Greece

The aim of this study was to investigate the prevalence and the implicated mechanisms of resistance against selected veterinary fluoroquinolones (enrofloxacin, marbofloxacin and pradofloxacin) among 101 Pseudomonas aeruginosa (n = 75) and Escherichia coli (n = 26) isolates collected from dogs suffering from otitis. Resistance ranged from 32.0% to 48.0% with differences not being considered statistically significant among the three agents or between the two bacterial species. However, individual MICs of pradofloxacin, the latest veterinary fluoroquinolone, were significantly lower than those of enrofloxacin, the oldest one, indicating an increased in vitro potency of the former antimicrobial. Pradofloxacin MIC90 was, additionally, the lowest (8 μg/ml), in E. coli, or among the lowest (8 μg/ml), in P. aeruginosa isolates. Resistance was in most cases associated with topoisomerase substitutions, with patterns GyrA:V73G in P. aeruginosa and GyrA:S83L+D87N/ParC:S58I+A86V in E. coli being reported for the first time in small animal isolates. Only 6.7% and 15.4% of P. aeruginosa and E. coli otitis isolates, respectively, carried plasmid-mediated quinolone resistance (PMQR) genes, which, moreover, contributed minimally to resistance. Efflux pump activity was additionally detected in resistant E. coli isolates, even those lacking topoisomerase substitutions or PMQR genes. The emergence of resistance in the canine otitis isolates seemed to be associated with previous, prolonged systemic fluoroquinolone administration. In any case, antimicrobial susceptibility testing should guide the selection of systemic FQs for the treatment of canine otitis. © 2017 Elsevier B.V

Prevalence and mechanisms of resistance to fluoroquinolones in Pseudomonas aeruginosa and Escherichia coli isolates recovered from dogs suffering from otitis in Greece

The aim of this study was to investigate the prevalence and the implicated mechanisms of resistance against selected veterinary fluoroquinolones (enrofloxacin, marbofloxacin and pradofloxacin) among 101 Pseudomonas aeruginosa (n = 75) and Escherichia coli (n = 26) isolates collected from dogs suffering from otitis. Resistance ranged from 32.0% to 48.0% with differences not being considered statistically significant among the three agents or between the two bacterial species. However, individual MICs of pradofloxacin, the latest veterinary fluoroquinolone, were significantly lower than those of enrofloxacin, the oldest one, indicating an increased in vitro potency of the former antimicrobial. Pradofloxacin MIC90 was, additionally, the lowest (8 μg/ml), in E. coli, or among the lowest (8 μg/ml), in P. aeruginosa isolates. Resistance was in most cases associated with topoisomerase substitutions, with patterns GyrA:V73G in P. aeruginosa and GyrA:S83L+D87N/ParC:S58I+A86V in E. coli being reported for the first time in small animal isolates. Only 6.7% and 15.4% of P. aeruginosa and E. coli otitis isolates, respectively, carried plasmid-mediated quinolone resistance (PMQR) genes, which, moreover, contributed minimally to resistance. Efflux pump activity was additionally detected in resistant E. coli isolates, even those lacking topoisomerase substitutions or PMQR genes. The emergence of resistance in the canine otitis isolates seemed to be associated with previous, prolonged systemic fluoroquinolone administration. In any case, antimicrobial susceptibility testing should guide the selection of systemic FQs for the treatment of canine otitis. © 2017 Elsevier B.V