The Effect of Leachate on the Compacted and Consolidated Clay Soils

Solid waste landfills constitute a potential major threat to groundwater quality. Water present in the waste, rainwater infiltration during and/or after the landfilling process and groundwater penetration can result in the generation of leachate. Leachate is a kind of waste liquid consisting of waste contaminants. Clay soils are natural matters to minimize the permeability of natural soil liners in landfill areas. Some contaminants in the leachate can alter compacted clay soils and cause increasing or decreasing permeability. This study investigates effects of leachate on the permeability of the compacted and consolidated clay soils, thereby evaluating the effectiveness of these clay soils as liners in preventing groundwater contamination. To determine removal capability of compacted and consolidated clay soils, some metal ions (Fe(II), Mn(II)) are also measured in influent and effluent of the lab-scale reactor. According to results of this study, Fe(II) and Mn(II) removal efficiency increases with time. Fe(OH)3 and MnO2 precipitations on the clay soil particles increase oxidation rate depending on the autocatalytic effect. Also, in the beginning, some decrease has been observed in the compacted and consolidated clay soils permeability associated with the contamination. However, as time goes by, these results show that leachates may cause an increase in the permeability

Dexmedetomidine, an alpha 2A receptor agonist, triggers seizures unilaterally in GAERS during the pre-epileptic phase: does the onset of spike-and-wave discharges occur in a focal manner?

IntroductionThe genetic absence epilepsy rat from Strasbourg (GAERS) is a rat model for infantile absence epilepsy with spike-and-wave discharges (SWDs). This study aimed to investigate the potential of alpha 2A agonism to induce seizures during the pre-epileptic period in GAERS rats.MethodsStereotaxic surgery was performed on male pups and adult GAERS rats to implant recording electrodes in the frontoparietal cortices (right/left) under anesthesia (PN23–26). Following the recovery period, pup GAERS rats were subjected to electroencephalography (EEG) recordings for 2 h. Before the injections, pup epileptiform activity was examined using baseline EEG data. Dexmedetomidine was acutely administered at 0.6 mg/kg to pup GAERS rats 2–3 days after the surgery and once during the post-natal (PN) days 25–29. Epileptiform activities before injections triggered unilateral SWDs and induced sleep durations, and power spectral density was evaluated based on EEG traces.ResultsThe most prominent finding of this study is that unilateral SWD-like activities were induced in 47% of the animals with the intraperitoneal dexmedetomidine injection. The baseline EEGs of pup GAERS rats had no SWDs as expected since they are in the pre-epileptic period but showed low-amplitude non-rhythmic epileptiform activity. There was no difference in the duration of epileptiform activities between the basal EEG groups and DEX-injected unilateral SWD-like-exhibiting and non-SWD-like activities groups; however, the sleep duration of the unilateral SWD-like-exhibiting group was shorter. Power spectrum density (PSD) results revealed that the 1.75-Hz power in the left hemisphere peaks significantly higher than in the right.DiscussionAs anticipated, pup GAERS rats in the pre-epileptic stage showed no SWDs. Nevertheless, they exhibited sporadic epileptiform activities. Specifically, dexmedetomidine induced SWD-like activities solely within the left hemisphere. These observations imply that absence seizures might originate unilaterally in the left cortex due to α2AAR agonism. Additional research is necessary to explore the precise cortical focal point of this activity

REMOVAL OF NATURAL ORGANIC MATTER FROM DRINKING WATER BY HYBRID COAGULATION/ADSORPTION-MEMBRANE FILTRATION

The aim of this study is to determine both the changing value of dissolved organic carbon (DOC) in water samples taken from influent of Kagithane Drinking Water Treatment Plant in Istanbul, and determine the removal efficiency of DOC, by separately applying coagulation, adsorption and membrane filtration methods to obtain the desired limits these methods are capable of producing