Effect of carrier type on coupled transport kinetics of thiocyanate ions through liquid membranes

Coupled transport of thiocyanate ions through a liquid membrane containing quaternary ammonium chloride salts in chloroform was examined. The influences of the carrier type in the membrane phase on the coupled transport of thiocyanate ions were investigated. The kinetics of the coupled transport were analyzed in the formalism of two consecutive irreversible first-order reactions and the kinetic parameters (k(1d), k(2m), k(2a), R-m(max), t(max), j(d)(max), J(a)(max)) were also calculated. For the coupled transport of thiocyanate ions, quaternary ammonium chloride salts having different carbon atom numbers (C-n) used as carriers were found to increase thiocyanate ions transport efficiency with increasing carbon atom numbers. Tetradecyl trimethylammonium chloride (TDTMACl), hexadecyl trimethylammonium chloride (HDTMACl), and tetraoctyl ammonium chloride (TOACl) were found to be the most effective carrier types for transport of thiocyanate ions when C-n is greater than 16. The activation energies for maximum membrane entrance and exit fluxes were calculated as 32.45 kJ/mol and 34.75 kJ/mol, respectively. The values of the activation energy indicate that the process is controlled by species diffusion

Acute and chronic stress alter behavioral laterality in dogs

Data availability: Since Turkish Government Working Dogs were tested in this study, data are available from the authors upon reasonable request and with the permission of the Republic of Turkey, Ministry of Trade.:Copyright © The Author(s) 2023. Dogs are one of the key animal species in investigating the biological mechanisms of behavioral laterality. Cerebral asymmetries are assumed to be influenced by stress, but this subject has not yet been studied in dogs. This study aims to investigate the effect of stress on laterality in dogs by using two different motor laterality tests: the Kong™ Test and a Food-Reaching Test (FRT). Motor laterality of chronically stressed (n = 28) and emotionally/physically healthy dogs (n = 32) were determined in two different environments, i.e., a home environment and a stressful open field test (OFT) environment. Physiological parameters including salivary cortisol, respiratory rate, and heart rate were measured for each dog, under both conditions. Cortisol results showed that acute stress induction by OFT was successful. A shift towards ambilaterality was detected in dogs after acute stress. Results also showed a significantly lower absolute laterality index in the chronically stressed dogs. Moreover, the direction of the first paw used in FRT was a good predictor of the general paw preference of an animal. Overall, these results provide evidence that both acute and chronic stress exposure can change behavioral asymmetries in dogs.The Scientific and Technological Research Council of Turkey (TUBITAK) 1001 grant (no: 118O445); Open Access Publication Funds of the Ruhr-Universität Bochum; The Council of Higher Education 100/2000 Scholarship in Human Brain and Neuroscience subdivision; Japan Society for Promortion of Science (JSPS) a KAKENHI grant (JP21J00063)

Steam activation of biochars facilitates kinetics and pH-resilience of sulfamethazine sorption

Purpose: Sulfamethazine (SMT) is increasingly detected in environmental matrices due to its versatile use as antibiotics. We aimed to investigate the benefits and roles of steam activation of biochars with respect to SMT sorption kinetics and equilibrium sorption. Materials and methods: Biochars were produced from burcucumber plant and tea waste using a pyrolyzer at a temperature of 700 °C for 2 h. The biochar samples were treated with 5 mL min−1 of steam for an additional 45 min for post-synthesis steam activation. The SMT sorption on the unmodified and steam activated biochars were compared. Results and discussion: The time taken to reach equilibrium was significantly less for steam activated biochars (∼4 h) than non-activated biochars (>24 h). Up to 98 % of SMT could be removed from aqueous solutions by steam activated biochars. The sorption kinetic behaviors were well described by the pseudo-second model and SMT sorption rates of steam activated biochars (k2 ∼ 1.11–1.57 mg g−1 min−1) were significantly higher than that of the unmodified biochars (k2 ∼ 0.04–0.11 mg g−1 min−1) because of increased availability of accessible porous structure with averagely larger pore diameters. Moreover, the equilibrium sorption on the unmodified biochars was significantly influenced by increasing solution pH (∼30–50 % reduction) because of speciation change of SMT, whereas steam activated biochars manifested much stronger sorption resilience against pH variation (∼2–4 % reduction only) because the enhanced porosity offset the effect of unfavorable electrostatic repulsion. Conclusions: The observed features of steam activated biochars would render their applications more versatile and reliable in field throughout changeable environmental conditions. © 2015, Springer-Verlag Berlin Heidelberg