939 research outputs found
DISTRIBUTION OF HEAVY METALS CONCENTRATIONS IN SOILS AROUND THE INTERNATIONAL ATHENS AIRPORT (GREECE). AN ASSESSMENT ON PRELIMINARY DATA
Τα εδάφη, ως αποδέκτες της ατμοσφαιρικής απόθεσης μετάλλων, αποτελούν αξιόπιστους δείκτες ρύπανσης, ιδιαίτερα στις περιπτώσεις που εντοπίζονται πιθανές σημειακές πηγές ρύπανσης σε χερσαία οικοσυστήματα. Σκοπός της παρούσας μελέτης ήταν η εκτίμηση της κατανομής των συγκεντρώσεων του Cu, Zn, Fe, Mn, Ni, Cr και Ba σε εδάφη κοντά στο Διεθνές Αεροδρόμιο Αθηνών «Ελ. Βενιζέλος», στην Αττική. Σε 86 επιφανειακά δείγματα προσδιορίστηκαν οι ολικές συγκεντρώσεις μετάλλων, στο εκχύλισμα που προέκυψε μετά από κατεργασία με «aqua regia». Οι διάμεσες τιμές των συγκεντρώσεων του Cu, Zn, Fe, Mn, Ni, Cr και Ba ήταν 23, 81, 22x103 , 497, 87, 74, 75 και 423 mg kg-1 αντίστοιχα. Αν και οι διάμεσες τιμές δε θεωρούνται τόσο υψηλές, οι τιμές του ενενηκοστού εκατοστημόριου για ορισμένα μέταλλα θεωρούνται υψηλές, υποδεικνύοντας πιθανό εμπλουτισμό του εδάφους με τα μέταλλα αυτά. Επίσης, παρατηρήθηκε μια τάση για αυξημένες συγκεντρώσεις του Zn και Cr κατά μήκος του άξονα Βορράς-Νότος καθώς και του Pb, Cu και Ni στο βόρειο τμήμα της περιοχής που μελετήθηκε. Τα προκαταρκτικά αποτελέσματα που προέκυψαν, υποβλήθηκαν σε ανάλυση κατά συστάδες και σε αξιολόγηση των συντελεστών εμπλουτισμού των μετάλλων, ως μια πρώτη προσέγγιση του διαχωρισμού μεταξύ φυσικής και ανθρωπογενούς συνεισφοράς των μετάλλων στα εδάφη της περιοχής. Τόσο οι συντελεστές εμπλουτισμού όσο και η ανάλυση κατά συστάδες, υποδηλώνουν δευτερογενή συγκέντρωση των Pb, Cu και Zn στα εδάφη της υπό μελέτη περιοχής.Soils are receptors of atmospheric metal depositions and hence reliable indicators of pollution phenomena, especially for cases that potential site specific pollution sources are detected in terrestrial ecosystems. The purpose of this study was to assess the distribution of Cu, Zn, Fe, Mn, Ni, Cr, Pb, and Ba concentrations in soils nearby the International Athens Airport “El. Venizelos”, in Attica, Greece. Total metal concentrations were determined in 86 topsoil aqua regia extracts and the median values for Cu, Zn, Fe, Mn, Ni, Cr, Pb, and Ba concentrations were 23, 81, 22x103 , 497, 87, 74, 75, and 423 mg kg-1 respectively. Though median values are not considered as high, the 90th percentile concentration values for some metals are high, indicating possible soil enrichment by these metals. A tendency for increased concentrations of Zn and Cr along the north-south axis and of Pb, Cu and Ni at the northern part of the studied area was also observed. As a first approach to discriminate between natural and anthropogenic metal contributions in the soils of the area, the obtained preliminary data were subjected to cluster analysis and to the evaluation of metals Enrichment Factors (EFs). Both EF values and cluster analysis results suggested secondary Pb, Cu and Zn site specific accumulation in the soils of the studied area
Fusion of Synchronous Fluorescence Spectra with Application to Argan Oil for Adulteration Analysis
When synchronous fluorescence (SyF) spectroscopy is used for quantitative and qualitative analysis, selection of a useful wavelength interval between the excitation and emission wavelengths (Δλ) is needed. Presented is a fusion approach to combine Δλ intervals thereby negating the selection process. This study uses the fusion of SyF spectra to detect adulteration of argan oil by corn oil and quantitative analysis of the corn oil content. The SyF spectra were acquired by varying the excitation wavelength in the region 300-800 nm using Δλ wavelength intervals from 10 to 100 nm in steps of 10 nm producing 10 sets of SyF spectra. For quantitative analysis, two calibration approaches are evaluated with these 10 SyF spectral datasets. Multivariate calibration by partial least squares (PLS) and a univariate calibration process where the SyF spectra are summed over respective SyF spectral ranges, the area under the curve (AUC) method. For adulteration detection and quantitation of the corn oil, prediction errors decrease with fusion compared to individually using the 10 Δλ interval SyF spectral data sets. For this data set, the AUC method generally provides smaller prediction errors than PLS at individual Δλ intervals as well as with fusion of all 10 Δλ intervals
Pancytopenia due to Restrictive Food Intake in an Autistic Adult
Autism spectrum disorder (ASD) is a neuro-behavioral syndrome that develops in childhood and can be comorbid with restrictive and avoidant food intake disorder. This case details a young man who was hospitalized with pancytopenia due to restrictive nutritional intake related to his severe ASD. He was found to have undetectable vitamin B12 levels. His blood counts improved with transfusion, nutritional supplementation, and dental care. This report illustrates the importance of understanding ASD and potential medical complications of related behaviors
Restoration of Defaced Serial Numbers Using Lock-In Infrared Thermography (Part I)
Infrared thermal imaging is an evolving approach useful in non-destructive evaluation of materials for industrial and research purposes. This study investigates the use of this method in combination with multivariate data analysis as an alternative to chemical etching; a destructive method currently used to recover defaced serial numbers stamped in metal. This process involves several unique aspects, each of which works to overcome some pertinent challenges associated with the recovery of defaced serial numbers. Infrared thermal imaging of metal surfaces provides thermal images sensitive to local differences in thermal conductivity of regions of plastic strain existing below a stamped number. These strains are created from stamping pressures distorting the atomic crystalline structure of the metal and extend to depths beneath the stamped number. These thermal differences are quite small and thus not readily visible from the raw thermal images of an irregular surface created by removing the stamped numbers. As such, further enhancement is usually needed to identify the subtle variations. The multivariate data analysis method, principal component analysis, is used to enhance these subtle variations and aid the recovery of the serial numbers. Multiple similarity measures are utilised to match recovered numbers to several numerical libraries, followed by application of various fusion rules to achieve consensus identification
Genetic inhibition of neurotransmission reveals role of glutamatergic input to dopamine neurons in high-effort behavior
Midbrain dopamine neurons are crucial for many behavioral and cognitive functions. As the major excitatory input, glutamatergic afferents are important for control of the activity and plasticity of dopamine neurons. However, the role of glutamatergic input as a whole onto dopamine neurons remains unclear. Here we developed a mouse line in which glutamatergic inputs onto dopamine neurons are specifically impaired, and utilized this genetic model to directly test the role of glutamatergic inputs in dopamine-related functions. We found that while motor coordination and reward learning were largely unchanged, these animals showed prominent deficits in effort-related behavioral tasks. These results provide genetic evidence that glutamatergic transmission onto dopaminergic neurons underlies incentive motivation, a willingness to exert high levels of effort to obtain reinforcers, and have important implications for understanding the normal function of the midbrain dopamine system.Fil: Hutchison, M. A.. National Institutes of Health; Estados UnidosFil: Gu, X.. National Institutes of Health; Estados UnidosFil: Adrover, Martín Federico. National Institutes of Health; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Lee, M. R.. National Institutes of Health; Estados UnidosFil: Hnasko, T. S.. University of California at San Diego; Estados UnidosFil: Alvarez, V. A.. National Institutes of Health; Estados UnidosFil: Lu, W.. National Institutes of Health; Estados Unido
Glutamate transporter GLT-1 mediates N-acetylcysteine inhibition of cocaine reinstatement
Both pre-clinical and clinical studies indicate that N-acetylcysteine (NAC) may be useful in treating relapse to addictive drug use. Cocaine self-administration in rats reduces both cystine-glutamate exchange and glutamate transport via GLT-1 in the nucleus accumbens, and NAC treatment normalizes these two glial processes critical for maintaining glutamate homeostasis. However, it is not known if one or both of these actions by NAC is needed to inhibit relapse to cocaine seeking. To determine whether the restoration of GLT-1 and/or cystine-glutamate exchange is required for NAC to inhibit cue-induced reinstatement of cocaine seeking, we utilized the rat self-administration/extinction/reinstatement model of cocaine relapse. Rats were pre-treated in the nucleus accumbens with vivo-morpholino anti-sense oligomers targeting either GLT-1 or xCT (catalytic subunit of the cystine-glutamate exchanger) overlapping with daily NAC administration during extinction (100 mg/kg, i.p. for the last 5 days). Rats then underwent cue-induced reinstatement of active lever pressing in the absence of NAC, to determine if preventing NAC-induced restoration of one or the other protein was sufficient to block the capacity of chronic NAC to inhibit reinstatement. The vivo-morpholino suppression of xCT reduced cystine-glutamate exchange but did not affect NAC-induced reduction of reinstated cocaine seeking. In contrast, suppressing NAC-induced restoration of GLT-1 not only prevented NAC from inhibiting reinstatement, but augmented the capacity of cues to reinstate cocaine seeking. We hypothesized that the increased reinstatement after inhibiting NAC induction of GLT-1 resulted from increased extracellular glutamate, and show that augmented reinstatement is prevented by blocking mGluR5. Restoring GLT-1, not cystine-glutamate exchange, is a key mechanism whereby daily NAC reduces cue-induced cocaine reinstatement
Altered Ratio of D1 and D2 Dopamine Receptors in Mouse Striatum Is Associated with Behavioral Sensitization to Cocaine
BACKGROUND: Drugs of abuse elevate brain dopamine levels, and, in vivo, chronic drug use is accompanied by a selective decrease in dopamine D2 receptor (D2R) availability in the brain. Such a decrease consequently alters the ratio of D1R:D2R signaling towards the D1R. Despite a plethora of behavioral studies dedicated to the understanding of the role of dopamine in addiction, a molecular mechanism responsible for the downregulation of the D2R, in vivo, in response to chronic drug use has yet to be identified. METHODS AND FINDINGS: ETHICS STATEMENT: All animal work was approved by the Gallo Center IACUC committee and was performed in our AAALAC approved facility. In this study, we used wild type (WT) and G protein coupled receptor associated sorting protein-1 (GASP-1) knock out (KO) mice to assess molecular changes that accompany cocaine sensitization. Here, we show that downregulation of D2Rs or upregulation of D1Rs is associated with a sensitized locomotor response to an acute injection of cocaine. Furthermore, we demonstrate that disruption of GASP-1, that targets D2Rs for degradation after endocytosis, prevents cocaine-induced downregulation of D2Rs. As a consequence, mice with a GASP-1 disruption show a reduction in the sensitized locomotor response to cocaine. CONCLUSIONS: Together, our data suggests that changes in the ratio of the D1:D2R could contribute to cocaine-induced behavioral plasticity and demonstrates a role of GASP-1 in regulating both the levels of the D2R and cocaine sensitization
Rabies screen reveals GPe control of cocaine-triggered plasticity.
Identification of neural circuit changes that contribute to behavioural plasticity has routinely been conducted on candidate circuits that were preselected on the basis of previous results. Here we present an unbiased method for identifying experience-triggered circuit-level changes in neuronal ensembles in mice. Using rabies virus monosynaptic tracing, we mapped cocaine-induced global changes in inputs onto neurons in the ventral tegmental area. Cocaine increased rabies-labelled inputs from the globus pallidus externus (GPe), a basal ganglia nucleus not previously known to participate in behavioural plasticity triggered by drugs of abuse. We demonstrated that cocaine increased GPe neuron activity, which accounted for the increase in GPe labelling. Inhibition of GPe activity revealed that it contributes to two forms of cocaine-triggered behavioural plasticity, at least in part by disinhibiting dopamine neurons in the ventral tegmental area. These results suggest that rabies-based unbiased screening of changes in input populations can identify previously unappreciated circuit elements that critically support behavioural adaptations
Stress-Induced Reinstatement of Drug Seeking: 20 Years of Progress
In human addicts, drug relapse and craving are often provoked by stress. Since 1995, this clinical scenario has been studied using a rat model of stress-induced reinstatement of drug seeking. Here, we first discuss the generality of stress-induced reinstatement to different drugs of abuse, different stressors, and different behavioral procedures. We also discuss neuropharmacological mechanisms, and brain areas and circuits controlling stress-induced reinstatement of drug seeking. We conclude by discussing results from translational human laboratory studies and clinical trials that were inspired by results from rat studies on stress-induced reinstatement. Our main conclusions are (1) The phenomenon of stress-induced reinstatement, first shown with an intermittent footshock stressor in rats trained to self-administer heroin, generalizes to other abused drugs, including cocaine, methamphetamine, nicotine, and alcohol, and is also observed in the conditioned place preference model in rats and mice. This phenomenon, however, is stressor specific and not all stressors induce reinstatement of drug seeking. (2) Neuropharmacological studies indicate the involvement of corticotropin-releasing factor (CRF), noradrenaline, dopamine, glutamate, kappa/dynorphin, and several other peptide and neurotransmitter systems in stress-induced reinstatement. Neuropharmacology and circuitry studies indicate the involvement of CRF and noradrenaline transmission in bed nucleus of stria terminalis and central amygdala, and dopamine, CRF, kappa/dynorphin, and glutamate transmission in other components of the mesocorticolimbic dopamine system (ventral tegmental area, medial prefrontal cortex, orbitofrontal cortex, and nucleus accumbens). (3) Translational human laboratory studies and a recent clinical trial study show the efficacy of alpha-2 adrenoceptor agonists in decreasing stress-induced drug craving and stress-induced initial heroin lapse
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