The Use of Semipermeable Membrane Devices to Concentrate Chemicals in Oil Refinery Effluent on the Mackenzie River

To concentrate natural and refinery-derived inducers of mixed function oxygenase (MFO), semipermeable membrane devices (SPMDs) were deployed for 11-12 days in Norman Wells refinery effluent and upstream and downstream on the Mackenzie River, Northwest Territories, Canada. SPMDs, which are layflat polyethylene membrane tubes containing a thin film of purified triolein, absorb freely dissolved neutral organic chemicals that diffuse through the polyethylene membrane. Fish liver cells (Poeciliopsis lucida hepatoma; PLHC-1) were dosed with SPMD extracts; then MFO activity was determined. SPMDs from the effluent contained potent MFO inducers, equivalent to 4830-8700 pg 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD)/g SPMD. SPMDs from the site 0.5 km downstream of the refinery outfall also induced MFO, but downstream extracts were about 1/40 as potent as those from effluent-exposed SPMDs. Comparing sites on the Mackenzie River, extracts of SPMDs from downstream of the refinery outfall were over 20 times as potent as those from upstream SPMDs. Polyaromatic hydrocarbons (PAHs) and C1- to C3-substituted PAHs were abundant in extracts of SPMDs from the effluent and, to a lesser degree, in extracts of SPMDs from 0.5 km downstream. In effluent-exposed and downstream SPMDs, concentrations of parent PAHs were lower than those of C1-substituted PAHs. The highest concentrations were those of C2- and C3-substituted PAHs. It is unknown which compounds in the SPMDs caused the MFO induction, but there was a very strong correlation between the concentration of total C3-phenanthrene/anthracene in the SPMD extracts and MFO-induction potency. The study shows both the use of SPMDs as concentrators of neutral organic compounds in harsh environments (such as high temperature effluents and fast-flowing rivers) and the utility and sensitivity of the fish liver cell line for ranking MFO-inducing potencies of environmental SPMD extracts.Afin de concentrer les inducteurs naturels et dérivés de raffinerie de l'oxygénase à fonction mixte (OFM), on a déployé de l'équipement à membrane semi-perméable pendant une durée de 11 à 12 jours dans les effluents de l'usine de raffinage de Norman Wells, de même qu'en amont et en aval dans les eaux du Mackenzie (Territoires du Nord-Ouest, Canada). Ces systèmes, formés de tubes de membrane en polyéthylène aplatis contenant une mince pellicule de trioléine purifiée, absorbent abondamment les produits chimiques organiques neutres en solution qui se diffusent dans toute la membrane de polyéthylène. On a mis des extraits de cette membrane en contact avec des cellules de foie de poisson (hépatocarcinome de Poeciliopsis lucida; HCPL-1), puis on a déterminé l'activité de l'OFM. Les membranes provenant des effluents contenaient de puissants inducteurs d'OFM, équivalents à 4830-8700 pg de tétrachlorodibenzodioxine-p 2,3,7,8 (TCDD)/g de membrane. Les membranes provenant du lieu situé à 0,5 km en aval du déversoir étaient aussi des inducteurs d'OFM, mais environ quarante fois moins puissants que ceux provenant des membranes exposées directement aux effluents. En comparant les sites sur le Mackenzie, les extraits des membranes situées en aval du déversoir de la raffinerie étaient environ 20 fois plus puissants que ceux des membranes situées en amont. Les hydrocarbures aromatiques polycycliques (HAP) et les HAP de remplacement de formule C1 à C3 se trouvaient en abondance dans les extraits de membrane provenant des effluents et, à un degré moindre, dans les extraits de membrane provenant du lieu situé à 0,5 km en aval. Dans les membranes exposées aux effluents et aux eaux situées en aval, les concentrations des HAP mères étaient inférieures à celles des HAP de remplacement de formule C1. Les concentrations les plus fortes étaient celles des HAP de remplacement de formule C2 et C3. On ne sait pas quels composés présents dans les membranes ont causé l'induction de l'OFM, mais il existait une très forte corrélation entre la concentration totale de phénanthrène/anthracène dans les extraits de membrane et la puissance d'induction de l'OFM. L'étude démontre à la fois l'utilisation des membranes comme concentrateurs des composés organiques neutres dans un environnement difficile (tel celui d'effluents à haute température et de cours d'eau rapides) ainsi que l'utilité et la sensibilité de la lignée cellulaire de foie de poisson pour classer les extraits de membrane environnementale selon leur puissance d'induction de l'OFM

Remembrance of things practiced with fast and slow learning in cortical and subcortical pathways

13 pagesThe learning of motor skills unfolds over multiple timescales, with rapid initial gains in performance followed by a longer period in which the behavior becomes more refined, habitual, and automatized. While recent lesion and inactivation experiments have provided hints about how various brain areas might contribute to such learning, their precise roles and the neural mechanisms underlying them are not well understood. In this work, we propose neural- and circuit-level mechanisms by which motor cortex, thalamus, and striatum support motor learning. In this model, the combination of fast cortical learning and slow subcortical learning gives rise to a covert learning process through which control of behavior is gradually transferred from cortical to subcortical circuits, while protecting learned behaviors that are practiced repeatedly against overwriting by future learning. Together, these results point to a new computational role for thalamus in motor learning and, more broadly, provide a framework for understanding the neural basis of habit formation and the automatization of behavior through practice

Symptomology Associated with in Utero Exposures to Polysubstance in an Appalachian Population.

Neonatal abstinence syndrome (NAS) is seen as a very high rate at our institution in Huntington, West Virginia, and the majority of exposures are polysubstance in nature. Polysubstance can have different meaning for each region. At our institution, polysubstance is any combination of opioids, gabapentin, methamphetamine, cocaine, marijuana, benzodiazepines, nicotine or other neuroactive substances with 3-4 substances being the norm. Rapidly changing combinations of drug use and the lack of literature create a difficult situation for clinicians who are often reliant on treatment recommendations that lack references or conclusive data supporting the clinical approaches. Elucidating withdrawal symptoms consistent with in utero exposures to particular drug combinations is difficult. Many substances induce similar withdrawal symptoms in neonates and the vast majority of cases present as polysubstance exposure. Standard methodology often leads to a research approach which isolates populations and substance of exposure to determine the individual effects on the neonate. In some drug combinations, like opioid and gabapentin exposure, the substances in concert create symptoms and complications that are not observed with either drug alone. The history of responses to substance use epidemics has been to handle each drug as a separate disease process, this is no longer a viable option. The following is a review of the literature available discussing individual substance withdrawal characteristics in neonates combined with the clinical insight gained at our hospital from treating such high rates of complex polysubstance exposure

Altered Cortical Gyrification in Adults Who Were Born Very Preterm and Its Associations With Cognition and Mental Health

Background: The last trimester of pregnancy is a critical period for the establishment of cortical gyrification, and altered folding patterns have been reported following very preterm birth (\u3c 33 weeks of gestation) in childhood and adolescence. However, research is scant on the persistence of such alterations in adulthood and their associations with cognitive and psychiatric outcomes. Methods: We studied 79 very preterm and 81 age-matched full-term control adults. T1-weighted magnetic resonance images were used to measure a local gyrification index (LGI), indicating the degree of folding across multiple vertices of the reconstructed cortical surface. Group and group-by-sex LGI differences were assessed by means of per-vertex adjustment for cortical thickness and overall intracranial volume. Within-group correlations were also computed between LGI and functional outcomes, including general intelligence (IQ) and psychopathology. Results: Very preterm adults had significantly reduced LGI in extensive cortical regions encompassing the frontal, anterior temporal, and occipitoparietal lobes. Alterations in lateral fronto-temporal-parietal and medial occipitoparietal regions were present in both men and women, although men showed more extensive alterations. In both very preterm and control adults, higher LGI was associated with higher IQ and lower psychopathology scores, with the spatial distribution of these associations substantially differing between the two groups. Conclusions: Very preterm adults’ brains are characterized by significant and widespread local hypogyria, and these alterations might be implicated in cognitive and psychiatric outcomes. Gyrification reflects an early developmental process and provides a fingerprint for very preterm birth

Vision as a compensatory mechanism for disturbance rejection in upwind flight

Recent experimental results demonstrate that flies possess a robust tendency to orient towards the frontally-centered focus of the visual motion field that typically occurs during upwind flight. We present a closed loop flight model, with a control algorithm based on feedback of the location of the visual focus of contraction, which is affected by changes in wind direction. The feasibility of visually guided upwind orientation is demonstrated with a model derived from current understanding of the biomechanics and sensorimotor computation of insects. The matched filter approach used to model the visual system computations compares extremely well with open-loop experimental data

A Control-Oriented Analysis of Bio-inspired Visuomotor Convergence

Insects exhibit incredibly robust closed loop fight dynamics in the face of uncertainties. A fundamental principle contributing to this unparalleled behavior is rapid processing and convergence of visual sensory information to fight motor commands via spatial wide-field integration, accomplished by retinal motion pattern sensitive interneurons (LPTCs) in the lobula plate portion of the visual ganglia. With in a control- theoretic frame work, models for spatially continuous retinal image flow and wide-field integration processing are developed, establishing the connection between image flow kernels (retinal motion pattern sensitivities) and the feedback terms they represent. It is shown that these out puts are sufficient to stabilize speed regulation and terrain following tasks. Hence, extraction of global retinal motion cues through computationally efficient wide-field integration processing provides a novel and promising methodology for utilizing visual sensory information in autonomous robotic navigation and fight control applications