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| 2. |
- Carabante, Ivan, et al.
(författare)
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Reciprocal influence of arsenic and iron on the long-term immobilization of arsenic in contaminated soils
- 2018
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Ingår i: Environmental Arsenic in a Changing World. - London : Taylor & Francis. ; , s. 467-469
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Konferensbidrag (refereegranskat)abstract
- The main aim of this work was to evaluate the fate of arsenic associated with iron minerals in contaminated soils. The ageing behavior of synthetic arsenic-bearing poorly crystalline minerals – ferrihydrite and schwertmannite – was studied. Arsenic showed a passivation effect on poorly crystalline minerals, delaying their transformation towards more crystalline iron oxides. These results agreed well with studies performed on contaminated soils and sediments. These results are relevant in order to understand the long-term mobility of arsenic in contaminated soils and sediments. Iron oxides sequesters arsenic efficiently and, reciprocally, arsenic stabilize the mineral, delaying its transformation towards more crystalline phases.
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| 3. |
- Antelo, Juan, et al.
(författare)
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Stability of naturally occurring AMD–schwertmannite in the presence of arsenic and reducing agents
- 2021
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Ingår i: Journal of Geochemical Exploration. - : Elsevier. - 0375-6742 .- 1879-1689. ; 220
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Tidskriftsartikel (refereegranskat)abstract
- Secondary iron oxides formed in acid mine drainage, such as schwertmannite, are scavengers for metal(loid)s in mining environments. Increasing the understanding of the geochemical transformations of these minerals, as well as knowing how metal(loid)s affect these transformations, is crucial to ultimately predict the fate of these trace elements in acidic mine drainage and to minimize the potential environmental risk. In this study, transformation experiments have been conducted with a schwertmannite-rich sediment collected from a mining area and with synthesized schwertmannite as a reference material. The transformation of schwertmannite into goethite was studied as a function of the presence of arsenic, pH value, and redox conditions. Arsenic delayed the mineral transformation from pseudo-stable amorphous phases to more stable crystalline forms, especially at higher arsenic loadings and more acidic pH. Experiments in the presence of Fe(II) and ascorbic acid have proven that both components promote the mineral transformation or reductive dissolution of schwertmannite under anoxic conditions. The presence of arsenic reduced the catalytic effect of Fe(II), stabilizing the schwertmannite particles. On the other hand, arsenic had no effect on the reductive dissolution at these conditions when ascorbic acid was used as a reducing agent. © 2020 Elsevier B.V.
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| 4. |
- Carlini, V P, et al.
(författare)
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Decreased memory for novel object recognition in chronically food-restricted mice is reversed by acute ghrelin administration
- 2008
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Ingår i: Neuroscience. - : Elsevier BV. - 0306-4522 .- 1873-7544. ; 153:4, s. 929-34
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Tidskriftsartikel (refereegranskat)abstract
- It has been demonstrated, in normal and aged rats and mice, that acute i.c.v. ghrelin (Ghr) administration increases memory retention. In order to evaluate if this treatment, restores memory retention in animals exhibiting impaired memory, in the present work we selected a chronic food restriction mouse model (since undernutrition prejudices higher nervous functions). We employed adult female mice with 28 days of 50% food restriction and evaluated: a) behavioral performance using novel object recognition test for memory, and plus maze for anxiety-like behavior, b) some morphometric parameters as body and hepatic weights and c) plasma Ghr levels. The animals with 50% food restriction showed an increase in plasma Ghr levels and a decrease in morphometric parameters and in the percentage of novel object recognition time. When the peptide was i.c.v. injected in food-restricted animals (0.03, 0.3 or 3.0 nmol/microl), memory increases in relation to food-restricted mice injected with vehicle, reaching a performance similar to controls.
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| 5. |
- Carlini, V. P., et al.
(författare)
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Hippocampal effects of neuronostatin on memory, anxiety-like behavior and food intake in rats
- 2011
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Ingår i: Neuroscience. - : Elsevier BV. - 0306-4522 .- 1873-7544. ; 197, s. 145-152
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Tidskriftsartikel (refereegranskat)abstract
- A 13-amino acid peptide named neuronostatin (NST) encoded in the somatostatin pro-hormone has been recently reported. It is produced throughout the body, particularly in brain areas that have significant actions over the metabolic and autonomic regulation. The present study was performed in order to elucidate the functional role of NST on memory, anxiety-like behavior and food intake and the hippocampal participation in these effects. When the peptide was intra-hippocampally administered at 3.0 nmol/mu l, it impaired memory retention in both, object recognition and step-down test. Also, this dose blocked the hippocampal long-term potentiation (LTP) generation. When NST was intra-hippocampally administered at 0.3 nmol/mu l and 3.0 nmol/mu l, anxiolytic effects were observed. Also, the administration in the third ventricle at the higher dose (3.0 nmol/mu l) induced similar effects, and both doses reduced food intake. The main result of the present study is the relevance of the hippocampal formation in the behavioral effects induced by NST, and these effects could be associated to a reduced hippocampal synaptic plasticity.
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| 6. |
- Gustavsson, Johan, 1974, et al.
(författare)
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High-speed 850-nm VCSELs for 40 Gb/s transmission
- 2010
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- We have explored the possibility to extend the data transmission rate for standard 850-nm GaAs-based VCSELs beyond the 10 Gbit/s limit of today's commercially available directly-modulated devices. By sophisticated tailoring of the design for high-speed performance we demonstrate that 10 Gb/s is far from the upper limit. For example, the thermal conductivity of the bottom mirror is improved by the use of binary compounds, and the electrical parasitics are kept at a minimum by incorporating a large diameter double layered oxide aperture in the design. We also show that the intrinsic high speed performance is significantly improved by replacing the traditional GaAs QWs with strained InGaAs QWs in the active region. The best overall performance is achieved for a device with a 9 μm diameter oxide aperture, having in a threshold current of 0.6 mA, a maximum output power of 9 mW, a thermal resistance of 1.9 °C/mW, and a differential resistance of 80 Ω. The measured 3dB bandwidth exceeds 20 GHz, and we experimentally demonstrate that the device is capable of error-free transmission (BER
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| 7. |
- Paola Carlini, Valeria, et al.
(författare)
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Acute ghrelin administration reverses depressive-like behavior induced by bilateral olfactory bulbectomy in mice
- 2012
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Ingår i: Peptides. - : Elsevier. - 0196-9781 .- 1873-5169. ; 35:2, s. 160-165
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Tidskriftsartikel (refereegranskat)abstract
- This study aims to examine the antidepressant-like action of Ghrelin (Ghr), a hormone synthesized predominantly by gastrointestinal endocrine cells and released during periods of negative energy balance, in two behavioral models: tail suspension test (TST), a predictive model of antidepressant activity, and the olfactory bulbectomy (OB), an established animal model of depression. The reduction in the immobility time in the TST was the parameter used to assess antidepressant-like effect of Ghr. The depressive-like behavior in olfactory bulbectomized mice was inferred through the increase in the immobility time in the TST and the hyperlocomotor activity in the open-field test. Ghr produced antidepressant-like effect in TST (0.3 nmol/mu l, i.c.v.), and reversed OB-induced depressive-like behavior. In conclusion, these results provide clear evidence that an acute administration of ghrelin produce antidepressant-like effect in the TST and OB.
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| 8. |
- Paola Carlini, Valeria, et al.
(författare)
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Differential effects of fluoxetine and venlafaxine on memory recognition : Possible mechanisms of action
- 2012
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Ingår i: Progress in Neuro-psychopharmacology and Biological Psychiatry. - : Elsevier BV. - 0278-5846 .- 1878-4216. ; 38:2, s. 159-167
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Tidskriftsartikel (refereegranskat)abstract
- Serotonin-specific reuptake inhibitors (SSRI) and serotonin-norepinephrine reuptake inhibitors (SNRI) are antidepressant drugs commonly used to treat a wide spectrum of mood disorders (Wong and Licinio, 2001). Although they have been clinically used for more than 50 years, the molecular and cellular basis for the action of SSRIs and SNRIs is not clear. Considering that the changes in gene expression involved in the action of antidepressant drugs on memory have not been identified, in this study we investigated the impact of chronic treatment with a SSRI (fluoxetine) and a SNRI (venlafaxine) on the mRNA expression of genes related to memory cascade in the mouse hippocampus, namely, alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), nitric oxide synthase 1 (NOS1), neurotrophic tyrosine kinase receptor type 2 (TrKB), mitogen-activated protein kinases (MAPK/ERK) and serotonin transporter (SERT). Animals treated with fluoxetine 10 mg/Kg/day for 28 days showed a significant decrease in the percentage of time spent in the novel object recognition test (p <= 0.005) and induced MAPK1/ERK2 down-regulation (p = 0.005). Our results suggest that the effect on cognition could probably be explained by fluoxetine interference in the MAPK/ERK memory pathway. In contrast, chronic treatment with venlafaxine did not reduce MAPK1/ERK2 expression, suggesting that MAPK1/ERK2 down-regulation is not a common effect of all antidepressant drugs. Further studies are needed to examine the effect of chronic fluoxetine treatment on the ERK-CREB system, and to determine whether there is a causal relationship between the disruption of the ERK-CREB system and the effect of this antidepressant on memory performance. (c) 2012 Elsevier Inc. All rights reserved.
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| 9. |
- Poretti, María Belén, et al.
(författare)
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Reduced vasopressin receptors activation mediates the anti-depressant effects of fluoxetine and venlafaxine in bulbectomy model of depression
- 2016
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Ingår i: Psychopharmacology. - : Springer Science and Business Media LLC. - 0033-3158 .- 1432-2072. ; 233:6, s. 1077-1086
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Tidskriftsartikel (refereegranskat)abstract
- RATIONALE: In response to stress, corticotropin releasing hormone (CRH) and vasopressin (AVP) are released from the hypothalamus, activate their receptors (CRHR1, CRHR2 or AVPr1b), and synergistically act to induce adrenocorticotropic hormone (ACTH) release from the anterior pituitary. Overstimulation of this system has been frequently associated with major depression states.OBJECTIVE: The objective of the study is to assess the role of AVP and CRH receptors in fluoxetine and venlafaxine effects on the expression of depression-related behavior.METHODS: In an animal model of depression (olfactory bulbectomy in mice, OB), we evaluated the effects of fluoxetine or venlafaxine (both 10 mg/kg/day) chronic administration on depression-related behavior in the tail suspension test. Plasma levels of AVP, CRH, and ACTH were determined as well as participation of their receptors in the expression of depression related-behavior and gene expression of AVP and CRH receptors (AVPr1b, CRHR1, and CRHR2) in the pituitary gland.RESULTS: The expression of depressive-like behavior in OB animals was reversed by treatment with both antidepressants. Surprisingly, OB-saline mice exhibited increased AVP and ACTH plasma levels, with no alterations in CRH levels when compared to sham mice. Chronic fluoxetine or venlafaxine reversed these effects. In addition, a significant increase only in AVPr1b gene expression was found in OB-saline.CONCLUSION: The antidepressant therapy used seems to be more likely related to a reduced activation of AVP rather than CRH receptors, since a positive correlation between AVP levels and depressive-like behavior was observed in OB animals. Furthermore, a full restoration of depressive behavior was observed in OB-fluoxetine- or venlafaxine-treated mice only when AVP was centrally administered but not CRH.
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