Comparison of trihalomethane formation using chlorine-based disinfectants within a model system; Applications within point-of-use drinking water treatment

© 2019 Clayton, Thorn and Reynolds. Point-of-use (POU) drinking water treatment systems provide solutions for communities where centralized facilities are unavailable. Effective POU systems treat and reduce the number of pathogens in POU water supplies often employing disinfection. Chlorine disinfection results in the formation of disinfection by-products (DBPs), such as trihalomethanes (THMs), through the reaction of chlorine with natural organic matter (NOM) over time. Although THMs are known to be harmful to human health, little is known about their production within POU systems. This study compares the disinfectants; Electrochemically Activated Solutions (ECAS), hypochlorous acid (HOCl), and sodium hypochlorite (NaOCl), with respect to their potential to produce THMs within POU drinking water systems. Headspace solid-phase microextraction (HS-SPME) gas chromatography mass spectrometry (GC-MS) was utilized to quantify THMs in treated water samples containing NOM (Suwannee River humic acid, 4 mg L -1 ). All disinfection treatments were matched to free chlorine concentrations of 1, 3, and 5 mg L -1 , using reaction times of 1, 5, and 10 min. THMs were produced at free chlorine concentrations of 5 mg L -1 and at reaction times of 5 and 10 min for all disinfectants. ECAS or HOCl, resulted in the formation of significantly lower total THM concentrations across all reaction times and free chlorine concentrations, compared to NaOCl. ECAS can be generated at the POU requiring only water, salt and energy for production, and this study demonstrates that its use results in reduced formation of THMs, compared with NaOCl. Further work is required to replicate these findings within scaled-up POU water treatment systems

Alexithymia in schizophrenia

Changes in emotional and social behavior are considered to be amongst the most common and debilitating consequences of schizophrenia. However, little is known of the effects of schizophrenia on alexithymia, which refers to impairment in aspects of understanding emotions. In the current study, participants with schizophrenia (n = 29) and nonclinical controls (n = 30) completed self-report and performance-based measures of this construct, in addition to measures of cognitive functioning, clinical symptomatology, and negative affect. The results indicated that individuals with schizophrenia showed increased alexithymia as indexed by the performance task, with these difficulties related to cognitive functioning, and the specific clinical symptom of alogia. However, although the correlation between self-reported alexithymia and negative affect in the schizophrenia group was congruent with prior empirical research and theory, there were no group differences in perceived levels of alexithymia. It is suggested that alexithymia may not be affected per se in schizophrenia (as indicated by the lack of group differences on the self-report measure of this construct), but that schizophrenia-related difficulties do emerge in contexts where cognitive demands are incremented. © 2010 Psychology Press

Emotional valence modulates brain functional abnormalities in depression:Evidence from a meta-analysis of fMRI studies

<p>Models describing the neural correlates of biased emotion processing in depression have focused on increased activation of anterior cingulate and amygdala and decreased activation of striatum and dorsolateral prefrontal cortex. However, neuroimaging studies investigating emotion processing in depression have reported inconsistent results. This meta-analysis integrates these findings and examines whether emotional valence modulates such abnormalities. A systematic literature search identified 26 whole-brain and 18 region-of-interest studies. Peak coordinates and effect sizes were combined in an innovative parametric meta-analysis. Opposing effects were observed in the amygdala, striatum, parahippocampal, cerebellar, fusiform and anterior cingulate cortex, with depressed subjects displaying hyperactivation for negative stimuli and hypoactivation for positive stimuli. Anterior cingulate activity was also modulated by facial versus non-facial stimuli, in addition to emotional valence. Depressed subjects also showed reduced activity in left dorsolateral prefrontal cortex for negative stimuli and increased activity in orbitofrontal cortex for positive stimuli. Emotional valence is a moderator of neural abnormalities in depression, and therefore a critical feature to consider in models of emotional dysfunction in depression. (C) 2012 Elsevier Ltd. All rights reserved.</p>