Control of disinfection by-products and biodegradable organic matter through biological treatment

L'objectif de ce projet, commun à l'Agence Américaine pour la Protection de l'Environnement (USEPA) et l'Université de Cincinnati, est d'optimiser l'usage de la préozonation associée à des procédés biologiques pour le traitement de l'eau de la rivière Ohio en vue de produire une eau biologiquement stable, d'éliminer une partie importante de la demande en chlore, et de réduire le potentiel de formation des sous-produits de la disintection. Ce projet a été conduit à l'échelle pilote et à l'échelle du laboratoire. Pour le traitement biologique, des bioréacteurs, contenant un film biologique sur un sable acclimaté aux eaux de la rivière Ohio, ont été utilisé.Une attention particulière a été portée à l'étude des sous-produits de la disinfection (DBPs) et de leurs précurseurs.Les résultats de l'ozonation ont démontré la formation d'aldéhydes : formaidéhyde, méthyl glyoxal, glyoxal et acétaldéhyde. A l'exception du formaldéhyde, les aldéhydes augmentent avec l'augmentation de la dose d'ozone, puis se stabilisent à un rapport d'ozone/carbone organique total (O3/COT) de 0,7 mg/mg. La formaldéhyde continue à augmenter proportionnellement aux doses d'ozone. Après traitement biologique, la concentration en aldéhydes diminue au dessous de 1 µg/l.L'augmentation de la dose d'ozone augmente le carbone organique assimilable (COA), (COA P17 ou COA-NOX), ainsi que le carbone organique dissous biodégradable (CODE). Le COA atteint un maximum pour une dose O3/COT de 2 mg/mg, alors que le COU continue à augmenter avec l'augmentation de la dose d'ozone jusqu'à une dose O3/COT de 3 mg/mg.La demande en chlore est réduite par les deux traitements, soit l'ozonation soit les procédés biologiques, respectivement de 75 % par l'ozonation et 55 % par les traitements biologiques.Des résultats similaires ont été trouvés en ce qui concerne l'effet des différentes doses d'ozone et des traitements biologiques sur les précurseurs des composés organiques halogénés totaux (TOX), les trihalométhanes (THMs) et les acides acétiques halogénés (HAAs). Les précurseurs sont mesurés par le potentiel de formation (FP), (conditions expérimentales : 12 mg/l de chlore, 7 jours de contact, 25 °C et pH 6,5 - 7,2). A une dose d'O3/COD de 0,4 mg/mg, les TOXFP, les THMFP et les HAAFP sont diminué de 28 %, 23 %, et 33 % respectivement. L'abattement des TOXFP et des THMFP continue légèrement avec une augmentation de la dose d'ozone, alors que les HAAFP sont diminués de façon plus marquée avec une dose d'O3/COD de 0,87 mglmg. Avec le traitement biologique et même sans préozonation, les TOXFP, les THMFP et les HAAFP diminuent de 39 %, 38 %, et 73 % respectivement. Avec le couplage de l'ozonation et le traitement biologique, les TOXFP et les THMFP sont diminués de 30 à 50 %. Les HAAFP se stabilisent entre 30 et 40 µg/l pour toutes les doses étudiées.Le potentiel de formation de chloropicrine augmente par l'ozonation mais est réduit de suite par le traitement biologique, jusqu'à moins de 0,2 µg/l.Donc, pour éliminer les sous-produits de la disinfection, la concentration optimale d'ozone pour l'eau de la rivière Ohio serait entre 0,6 à 1,0 mg/mg (O3/COT).En conclusion, l'ozonation diminue la demande en chlore ainsi que les précurseurs des composés organiques halogénés (TOX, THM et HAA). Par contre, l'ozonation produit des autres sous-produits comme les aldéhydes et le chloropicrine et augmente le COA et le COD biodégradable, qui sert par la suite de substrat aux microorganismes. Les procédés biologiques sont efficaces pour diminuer les sous-produits d'oxydation, la demande en chlore et les précurseurs des composés organiques halogénés (TOX, THM et HAA).Cet abattement permettra l'application de moins de chlore pour maintenir un résiduel dans le réseau et permettra aux usines d'atteindre des normes plus sévères que celles qui sont en effet maintenant.The optimal use of ozonation as a pretreatment process prior to biological treatment of Ohio River water was investigated at both the bench (batch) and pilot-plant (continuous flow) scale. The study focused on disinfection by-products (DBPs) and DBP precursor compounds and on the production of biologically stable water. Biotreatment was achieved using a bench-scale fixed-film reactor with sand acclimated to the raw Ohio River water.Ozonation was found to create a number of aldehydes, in particular formaldehyde, methyl glyoxal, glyoxal and acetaldehyde. With the exception of formaldehyde, a plateau in the aldehyde yield occurred at an ozone to total organic carbon (03/TOC) ratio of 0,7 mg/mg, while formaldehyde increased with increasing ozone dose. After biotreatment, the concentration of aldehydes were below 1 µg/1. Increasing ozone doses were also found to increase the assimilable organic carbon (AOC), by both NOX and P17 procedures, and the biodegradable dissolved organic carton (BDOC). The AOC values showed a maximum at about an 03/TOC ratio of 2 mg/mg, white the BDOC continued to increase with the highest ozone dose : an 03/TOC ratio of 2,8 mg/mg.Both ozonation and biotreatment were fond to decrease the chlorine demand by up to 75 % for ozonation and 55 % for biotreatment.Similar trends were found for the impact of ozonation and biotreatment on the precursor compounds for total organic halogen (TOX), total trihalomethanes (TTHMs) and total haloacetic acids (THAAs), as measured by the formation potential (FP) test : 12 mg/l chlorine, 7 days, 25 °C, 6.5-7.2 pH. An ozone dose of 0.4 03/DOC (mg/mg) decreased the TOXFP, TTHMFP and THAAFP by 28 %, 23 % and 33 %, respectively. Further increases in ozone only marginally increased the amount of the TOXFP and TTHMFP removed, white a maximum removal of 53 % of the THAAFP occurred at 03/DOC ratio of 0.87 mg/mg. Biotreatment of the nonozonated samples yielded 39 %, 38 % and 73 % removal of the TOXFP, TTHMFP and THAAFP, respectively. Biotreatment of the ozonated sample yielded a 30 to 50 % reduction in TOXFP and TTHMFP, while a constant level of 30 to 40 µg/l of THAAFP was achieved. Chloropicrin formation potential increased with ozone dose, but subsequent biotreatment reduced it to below 0.2 µg/l.Ozonation was Pound to oxidize chorine demand and the precursors for TOX, THM and HAAs. However, it created chloropicrin precursors, aldehydes and other biodegradable organic matter. Biotreatment was found to further reduce the chlorine demand, the precursors for TOX, THMs and HAAs and reduce the ozone created disinfection by-products

Robustness and Enhancement of Neural Synchronization by Activity-Dependent Coupling

We study the synchronization of two model neurons coupled through a synapse having an activity-dependent strength. Our synapse follows the rules of Spike-Timing Dependent Plasticity (STDP). We show that this plasticity of the coupling between neurons produces enlarged frequency locking zones and results in synchronization that is more rapid and much more robust against noise than classical synchronization arising from connections with constant strength. We also present a simple discrete map model that demonstrates the generality of the phenomenon.Comment: 4 pages, accepted for publication in PR

Aberrant network connectivity during error processing in patients with schizophrenia

BACKGROUND: Neuroimaging methods have pointed to deficits in the interaction of large-scale brain networks in patients with schizophrenia. Abnormal connectivity of the right anterior insula (AI), a central hub of the salience network, is frequently reported and may underlie patients’ deficits in adaptive salience processing and cognitive control. While most previous studies used resting state approaches, we examined right AI interactions in a task-based fMRI study. METHODS: Patients with schizophrenia and healthy controls performed an adaptive version of the Eriksen Flanker task that was specifically designed to ensure a comparable number of errors between groups. RESULTS: We included 27 patients with schizophrenia and 27 healthy controls in our study. The between-groups comparison replicated the classic finding of reduced activation in the midcingulate cortex (MCC) in patients with schizophrenia during the commission of errors while controlling for confounding factors, such as task performance and error frequency, which have been neglected in many previous studies. Subsequent psychophysiological interaction analysis revealed aberrant functional connectivity (FC) between the right AI and regions in the inferior frontal gyrus and temporoparietal junction. Additionally, FC between the MCC and the dorsolateral prefrontal cortex was reduced. LIMITATIONS: As we examined a sample of medicated patients, effects of antipsychotic medication may have influenced our results. CONCLUSION: Overall, it appears that schizophrenia is associated with impairment of networks associated with detection of errors, refocusing of attention, superordinate guiding of cognitive control and their respective coordination

Opioid receptor activation triggering downregulation of cAMP improves effectiveness of anti-cancer drugs in treatment of glioblastoma

Glioblastoma are the most frequent and malignant human brain tumors, having a very poor prognosis. The enhanced radio- and chemoresistance of glioblastoma and the glioblastoma stem cells might be the main reason why conventional therapies fail. The second messenger cyclic AMP (cAMP) controls cell proliferation, differentiation, and apoptosis. Downregulation of cAMP sensitizes tumor cells for anti-cancer treatment. Opioid receptor agonists triggering opioid receptors can activate inhibitory Gi proteins, which, in turn, block adenylyl cyclase activity reducing cAMP. In this study, we show that downregulation of cAMP by opioid receptor activation improves the effectiveness of anti-cancer drugs in treatment of glioblastoma. The µ-opioid receptor agonist D,L-methadone sensitizes glioblastoma as well as the untreatable glioblastoma stem cells for doxorubicin-induced apoptosis and activation of apoptosis pathways by reversing deficient caspase activation and deficient downregulation of XIAP and Bcl-xL, playing critical roles in glioblastomas' resistance. Blocking opioid receptors using the opioid receptor antagonist naloxone or increasing intracellular cAMP by 3-isobutyl-1-methylxanthine (IBMX) strongly reduced opioid receptor agonist-induced sensitization for doxorubicin. In addition, the opioid receptor agonist D,L-methadone increased doxorubicin uptake and decreased doxorubicin efflux, whereas doxorubicin increased opioid receptor expression in glioblastomas. Furthermore, opioid receptor activation using D,L-methadone inhibited tumor growth significantly in vivo. Our findings suggest that opioid receptor activation triggering downregulation of cAMP is a promising strategy to inhibit tumor growth and to improve the effectiveness of anti-cancer drugs in treatment of glioblastoma and in killing glioblastoma stem cells

GABA-enhanced collective behavior in neuronal axons underlies persistent gamma-frequency oscillations

Gamma (30–80 Hz) oscillations occur in mammalian electroencephalogram in a manner that indicates cognitive relevance. In vitro models of gamma oscillations demonstrate two forms of oscillation: one occurring transiently and driven by discrete afferent input and the second occurring persistently in response to activation of excitatory metabotropic receptors. The mechanism underlying persistent gamma oscillations has been suggested to involve gap-junctional communication between axons of principal neurons, but the precise relationship between this neuronal activity and the gamma oscillation has remained elusive. Here we demonstrate that gamma oscillations coexist with high-frequency oscillations (>90 Hz). High-frequency oscillations can be generated in the axonal plexus even when it is physically isolated from pyramidal cell bodies. They were enhanced in networks by nonsomatic -aminobutyric acid type A (GABAA) receptor activation, were modulated by perisomatic GABAA receptor-mediated synaptic input to principal cells, and provided the phasic input to interneurons required to generate persistent gamma-frequency oscillations. The data suggest that high-frequency oscillations occurred as a consequence of random activity within the axonal plexus. Interneurons provide a mechanism by which this random activity is both amplified and organized into a coherent network rhythm

Gamma and beta frequency oscillations in response to novel auditory stimuli: A comparison of human electroencephalogram (EEG) data with in vitro models

Investigations using hippocampal slices maintained in vitro have demonstrated that bursts of oscillatory field potentials in the gamma frequency range (30-80 Hz) are followed by a slower oscillation in the beta 1 range (12-20 Hz). In this study, we demonstrate that a comparable gamma-to-beta transition is seen in the human electroencephalogram (EEG) in response to novel auditory stimuli. Correlations between gamma and beta 1 activity revealed a high degree of interdependence of synchronized oscillations in these bands in the human EEG. Evoked (stimulus-locked) gamma oscillations preceded beta 1 oscillations in response to novel stimuli, suggesting that this may be analogous to the gamma-to-beta shift observed in vitro. Beta 1 oscillations were the earliest discriminatory responses to show enhancement to novel stimuli, preceding changes in the broad-band event-related potential (mismatch negativity). Later peaks of induced beta activity over the parietal cortex were always accompanied by an underlying gamma frequency oscillation as seen in vitro. A further analogy between in vitro and human recordings was that both gamma and beta oscillations habituated markedly after the initial novel stimulus presentation

Explanation and elaboration of the SQUIRE (Standards for Quality Improvement Reporting Excellence) Guidelines, V.2.0: examples of SQUIRE elements in the healthcare improvement literature

Since its publication in 2008, SQUIRE (Standards for Quality Improvement Reporting Excellence) has contributed to the completeness and transparency of reporting of quality improvement work, providing guidance to authors and reviewers of reports on healthcare improvement work. In the interim, enormous growth has occurred in understanding factors that influence the success, and failure, of healthcare improvement efforts. Progress has been particularly strong in three areas: the understanding of the theoretical basis for improvement work; the impact of contextual factors on outcomes; and the development of methodologies for studying improvement work. Consequently, there is now a need to revise the original publication guidelines. To reflect the breadth of knowledge and experience in the field, we solicited input from a wide variety of authors, editors and improvement professionals during the guideline revision process. This Explanation and Elaboration document (E&E) is a companion to the revised SQUIRE guidelines, SQUIRE 2.0. The product of collaboration by an international and interprofessional group of authors, this document provides examples from the published literature, and an explanation of how each reflects the intent of a specific item in SQUIRE. The purpose of the guidelines is to assist authors in writing clearly, precisely and completely about systematic efforts to improve the quality, safety and value of healthcare services. Authors can explore the SQUIRE statement, this E&E and related documents in detail at http://www.squire-statement.org

Invariance and variability in interaction error-related potentials and their consequences for classification

© 2017 IOP Publishing Ltd. Objective. This paper discusses the invariance and variability in interaction error-related potentials (ErrPs), where a special focus is laid upon the factors of (1) the human mental processing required to assess interface actions (2) time (3) subjects. Approach. Three different experiments were designed as to vary primarily with respect to the mental processes that are necessary to assess whether an interface error has occurred or not. The three experiments were carried out with 11 subjects in a repeated-measures experimental design. To study the effect of time, a subset of the recruited subjects additionally performed the same experiments on different days. Main results. The ErrP variability across the different experiments for the same subjects was found largely attributable to the different mental processing required to assess interface actions. Nonetheless, we found that interaction ErrPs are empirically invariant over time (for the same subject and same interface) and to a lesser extent across subjects (for the same interface). Significance. The obtained results may be used to explain across-study variability of ErrPs, as well as to define guidelines for approaches to the ErrP classifier transferability problem

Never gonna GIF you up:Analyzing the cultural significance of the animated GIF

The animated Graphics Interchange Format (GIF) is a digital file format with a long history within internet cultures and digital content. Emblematic of the early Web, the GIF fell from favor in the late 1990s before experiencing a resurgence that has seen the format become ubiquitous within digital communication. While the GIF has certain technical affordances that make it highly versatile, this is not the sole reason for its ubiquity. Instead, GIFs have become a key communication tool in contemporary digital cultures thanks to a combination of their features, constraints, and affordances. GIFs are polysemic, largely because they are isolated snippets of larger texts. This, combined with their endless, looping repetition, allows them to relay multiple levels of meaning in a single GIF. This symbolic complexity makes them an ideal tool for enhancing two core aspects of digital communication: the performance of affect and the demonstration of cultural knowledge. The combined impact of these capabilities imbues the GIF with resistant potential, but it has also made it ripe for commodification. In this article, we outline and articulate the GIF’s features and affordances, investigate their implications, and discuss their broader significance for digital culture and communication

Rationale and design of a multicenter randomized controlled trial on a 'minimal intervention' in Dutch army personnel with nonspecific low back pain [ISRCTN19334317]

BACKGROUND: Researchers from the Royal Netherlands Army are studying the potential of isolated lumbar extensor training in low back pain in their working population. Currently, a randomized controlled trial is carried out in five military health centers in The Netherlands and Germany, in which a 10-week program of not more than 2 training sessions (10–15 minutes) per week is studied in soldiers with nonspecific low back pain for more than 4 weeks. The purpose of the study is to investigate the efficacy of this 'minimal intervention program', compared to usual care. Moreover, attempts are made to identify subgroups of different responders to the intervention. METHODS: Besides a baseline measurement, follow-up data are gathered at two short-term intervals (5 and 10 weeks after randomization) and two long-term intervals (6 months and one year after the end of the intervention), respectively. At every test moment, participants fill out a compound questionnaire on a stand-alone PC, and they undergo an isometric back strength measurement on a lower back machine. Primary outcome measures in this study are: self-assessed degree of complaints and degree of handicap in daily activities due to back pain. In addition, our secondary measurements focus on: fear of movement/(re-) injury, mental and social health perception, individual back extension strength, and satisfaction of the patient with the treatment perceived. Finally, we assess a number of potential prognostic factors: demographic and job characteristics, overall health, the degree of physical activity, and the attitudes and beliefs of the physiotherapist towards chronic low back pain. DISCUSSION: Although a substantial number of trials have been conducted that included lumbar extension training in low back pain patients, hardly any study has emphasized a minimal intervention approach comparable to ours. For reasons of time efficiency and patient preferences, this minimal sports medicine approach of low back pain management is interesting for the population under study, and possibly for comparable working populations with physical demanding job activities