| 1. |
- Monasterio, M., et al.
(författare)
-
Cause of the fragile-to-strong transition observed in water confined in C-S-H gel
- 2013
-
Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 1089-7690 .- 0021-9606. ; 139:16
-
Tidskriftsartikel (refereegranskat)abstract
- In this study, the rotational dynamics of hydration water confined in calcium-silicate-hydrate (C-S-H) gel with a water content of 22 wt.% was studied by broadband dielectric spectroscopy in broad temperature (110-300 K) and frequency (10(-1)-10(8) Hz) ranges. The C-S-H gel was used as a 3D confining system for investigating the possible existence of a fragile-to-strong transition for water around 220 K. Such transition was observed at 220 K in a previous study [Y. Zhang, M. Lagi, F. Ridi, E. Fratini, P. Baglioni, E. Mamontov and S. H. Chen, J. Phys.: Condens. Matter 20, 502101 (2008)] on a similar system, and it was there associated with a hidden critical point of bulk water. However, based on the experimental results presented here, there is no sign of a fragile-to-strong transition for water confined in C-S-H gel. Instead, the fragile-to-strong transition can be explained by a merging of two different relaxation processes at about 220 K. (C) 2013 AIP Publishing LLC.
|
|
| 2. |
- Bertram, Michael G., et al.
(författare)
-
Frontiers in quantifying wildlife behavioural responses to chemical pollution
- 2022
-
Ingår i: Biological Reviews. - : John Wiley & Sons. - 1464-7931 .- 1469-185X. ; 97:4
-
Tidskriftsartikel (refereegranskat)abstract
- Animal behaviour is remarkably sensitive to disruption by chemical pollution, with widespread implications for ecological and evolutionary processes in contaminated wildlife populations. However, conventional approaches applied to study the impacts of chemical pollutants on wildlife behaviour seldom address the complexity of natural environments in which contamination occurs. The aim of this review is to guide the rapidly developing field of behavioural ecotoxicology towards increased environmental realism, ecological complexity, and mechanistic understanding. We identify research areas in ecology that to date have been largely overlooked within behavioural ecotoxicology but which promise to yield valuable insights, including within- and among-individual variation, social networks and collective behaviour, and multi-stressor interactions. Further, we feature methodological and technological innovations that enable the collection of data on pollutant-induced behavioural changes at an unprecedented resolution and scale in the laboratory and the field. In an era of rapid environmental change, there is an urgent need to advance our understanding of the real-world impacts of chemical pollution on wildlife behaviour. This review therefore provides a roadmap of the major outstanding questions in behavioural ecotoxicology and highlights the need for increased cross-talk with other disciplines in order to find the answers.
|
|
| 3. |
- Castillo, N. A., et al.
(författare)
-
Understanding pharmaceutical exposure and the potential for effects in marine biota : A survey of bonefish (Albula vulpes) across the Caribbean Basin
- 2024
-
Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 349
-
Tidskriftsartikel (refereegranskat)abstract
- Most research on pharmaceutical presence in the environment to date has focused on smaller scale assessments of freshwater and riverine systems, relying mainly on assays of water samples, while studies in marine ecosystems and of exposed biota are sparse. This study investigated the pharmaceutical burden in bonefish (Albula vulpes), an important recreational and artisanal fishery, to quantify pharmaceutical exposure throughout the Caribbean Basin. We sampled 74 bonefish from five regions, and analyzed them for 102 pharmaceuticals. We assessed the influence of sampling region on the number of pharmaceuticals, pharmaceutical assemblage, and risk of pharmacological effects. To evaluate the risk of pharmacological effects at the scale of the individual, we proposed a metric based on the human therapeutic plasma concentration (HTPC), comparing measured concentrations to a threshold of 1/3 the HTPC for each pharmaceutical. Every bonefish had at least one pharmaceutical, with an average of 4.9 and a maximum of 16 pharmaceuticals in one individual. At least one pharmaceutical was detected in exceedance of the 1/3 HTPC threshold in 39% of bonefish, with an average of 0.6 and a maximum of 11 pharmaceuticals exceeding in a Key West individual. The number of pharmaceuticals (49 detected in total) differed across regions, but the risk of pharmacological effects did not (23 pharmaceuticals exceeded the 1/3 HTPC threshold). The most common pharmaceuticals were venlafaxine (43 bonefish), atenolol (36), naloxone (27), codeine (27), and trimethoprim (24). Findings suggest that pharmaceutical detections and concentration may be independent, emphasizing the need to monitor risk to biota regardless of exposure diversity, and to focus on risk quantified at the individual level. This study supports the widespread presence of pharmaceuticals in marine systems and shows the utility of applying the HTPC to assess the potential for pharmacological effects, and thus quantify impact of exposure at large spatial scales.
|
|
| 4. |
- Cerveny, Daniel, et al.
(författare)
-
Environmentally relevant concentration of caffeine : effect on activity and circadian rhythm in wild perch
- 2022
-
Ingår i: Environmental Science and Pollution Research. - : Springer. - 0944-1344 .- 1614-7499. ; 29:36, s. 54264-54272
-
Tidskriftsartikel (refereegranskat)abstract
- We studied the ecological consequences of widespread caffeine contamination by conducting an experiment focused on changes in the behavioral traits of wild perch (Perca fluviatilis) after waterborne exposure to 10 μg L−1 of caffeine. We monitored fish swimming performance during both light and dark conditions to study the effect of caffeine on fish activity and circadian rhythm, using a novel three-dimensional tracking system that enabled positioning even in complete darkness. All individuals underwent three behavioral trials—before exposure, after 24 h of exposure, and after 5 days of exposure. We did not observe any effect of the given caffeine concentration on fish activity under light or dark conditions. Regardless of caffeine exposure, fish swimming performance was significantly affected by both the light-dark conditions and repeating of behavioral trials. Individuals in both treatments swam significantly more during the light condition and their activity increased with time as follows: before exposure < after 24 h of exposure < after 5 days of exposure. We confirmed that the three-dimensional automated tracking system based on infrared sensors was highly effective for conducting behavioral experiments under completely dark conditions.
|
|
| 5. |
- Cerveny, D., et al.
(författare)
-
Water temperature affects the biotransformation and accumulation of a psychoactive pharmaceutical and its metabolite in aquatic organisms
- 2021
-
Ingår i: Environment International. - : Elsevier. - 0160-4120 .- 1873-6750. ; 155
-
Tidskriftsartikel (refereegranskat)abstract
- Pharmaceutically active compounds (PhACs) have been shown to accumulate in aquatic and riparian food-webs. Yet, our understanding of how temperature, a key environmental factor in nature, affects uptake, biotransformation, and the subsequent accumulation of PhACs in aquatic organisms is limited. In this study, we tested to what extent bioconcentration of an anxiolytic drugs (temazepam and oxazepam) is affected by two temperature regimes (10 and 20 °C) and how the temperature affects the temazepam biotransformation and subsequent accumulation of its metabolite (oxazepam) in aquatic organisms. We used European perch (Perca fluviatilis) and dragonfly larvae (Sympetrum sp.), which represent predator and prey species of high ecological relevance in food chains of boreal and temperate aquatic ecosystems. Experimental organisms were exposed to target pharmaceuticals at a range of concentrations (0.2–6 µg L−1) to study concentration dependent differences in bioconcentration and biotransformation. We found that the bioconcentration of temazepam in perch was significantly reduced at higher temperatures. Also, temperature had a strong effect on temazepam biotransformation in the fish, with the production and subsequent accumulation of its metabolite (oxazepam) being two-fold higher at 20 °C compared to 10 °C. In contrast, we found no temperature dependency for temazepam bioconcentration in dragonfly larvae and no detectable biotransformation of the parent compound that would result in measurable concentrations of oxazepam in this organism. Our results highlight that while organisms may share the same aquatic ecosystem, their exposure to PhACs may change differently across temperature gradients in the environment.
|
|
| 6. |
- Cerveny, S., et al.
(författare)
-
Confined Water as Model of Supercooled Water
- 2016
-
Ingår i: Chemical Reviews. - : American Chemical Society (ACS). - 0009-2665 .- 1520-6890. ; 116:13, s. 7608-7625
-
Forskningsöversikt (refereegranskat)abstract
- Water in confined geometries has obvious relevance in biology, geology, and other areas where the material properties are strongly dependent on the amount and behavior of water in these types of materials. Another reason to restrict the size of water domains by different types of geometrical confinements has been the possibility to study the structural and dynamical behavior of water in the deeply supercooled regime (e.g., 150-230 K at ambient pressure), where bulk water immediately crystallizes to ice. In this paper we give a short review of studies with this particular goal. However, from these studies it is also clear that the interpretations of the experimental data are far from evident. Therefore, we present three main interpretations to explain the experimental data, and we discuss their advantages and disadvantages. Unfortunately, none of the proposed scenarios is able to predict all the observations for supercooled and glassy bulk water, indicating that either the structural and dynamical alterations of confined water are too severe to make predictions for bulk water or the differences in how the studied water has been prepared (applied cooling rate, resulting density of the water, etc.) are too large for direct and quantitative comparisons.
|
|
| 7. |
|
|
| 8. |
- Cerveny, S., et al.
(författare)
-
Dynamics of supercooled water in a biological model system of the amino acid L-lysine
- 2014
-
Ingår i: Physical Chemistry Chemical Physics. - : Royal Society of Chemistry (RSC). - 1463-9084 .- 1463-9076. ; 16:40, s. 22382-22390
-
Tidskriftsartikel (refereegranskat)abstract
- The dynamics of supercooled water in aqueous solutions of the single amino acid L-lysine has been studied by broadband dielectric spectroscopy. The chosen biological system is unique in the sense that the water content is high enough to fully dissolve the amino acid, but low enough to avoid crystallisation to ice at any temperature. This is not possible to achieve for proteins or other larger biomolecules, where either hydrated samples without ice or solutions with large quantities of ice, or a cryoprotectant sugar, have to be studied at low temperatures. Thus, it is a key finding to be able to study water and biomolecular dynamics in a non-crystallized and biologically realistic solution at supercooled temperatures. Here, we focus on the water dynamics in this unique biological solution of L-lysine and water. We show that this unique system also gives rise to unique water dynamics, since, for the first time, a continuation of a cooperative (alpha-like) water relaxation is observed after a crossover to a more local beta-like water relaxation has occurred with decreasing temperature. This implies that the supercooled water in the biological solution shows a twofold relaxation behaviour, with one relaxation identical to the main relaxation of water in hard confinements and one relaxation almost identical to the main water relaxation in ordinary aqueous solutions.
|
|
| 9. |
- Cerveny, S., et al.
(författare)
-
Evidence of Coupling between the Motions of Water and Peptides
- 2016
-
Ingår i: Journal of Physical Chemistry Letters. - : American Chemical Society (ACS). - 1948-7185. ; 7:20, s. 4093-4098
-
Tidskriftsartikel (refereegranskat)abstract
- Studies of protein dynamics at low temperatures are generally performed on hydrated powders and not in biologically realistic solutions of water because of water crystallization. However, here we avoid the problem of crystallization by reducing the size of the biomolecules. We have studied oligomers of the amino acid L-lysine, fully dissolved in water, and our dielectric relaxation data show that the glass transition-related dynamics of the oligomers is determined by the water dynamics, in a way similar to that previously observed for solvated proteins. This implies that the crucial role of water for protein dynamics can be extended to other types of macromolecular systems, where water is also able to determine their conformational fluctuations. Using the energy landscape picture of macromolecules, the thermodynamic criterion for such solvent-slaved macromolecular motions may be that the macromolecules need the entropy contribution from the solvent to overcome the enthalpy barriers between different conformational substates.
|
|
| 10. |
|
|
| 11. |
|
|
| 12. |
|
|
| 13. |
- Cerveny, S., et al.
(författare)
-
Water dynamics in the hydration shells of biological and non-biological polymers
- 2019
-
Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 1089-7690 .- 0021-9606. ; 150:23
-
Tidskriftsartikel (refereegranskat)abstract
- The dynamics of water at supercooled temperatures in aqueous solutions of different types of solutes has been deeply analyzed in the literature. In these previous works and in most of the cases, a single relaxation of water molecules is observed. In this work, we analyze the dynamics of water in solutions for which a dual relaxation of water molecules is experimentally measured. We discuss the criteria for observing these two water relaxations in these specific solutions and their most likely origins. We also discuss how these two water relaxations relate to the relaxation behavior of bulk water and how the slower one is coupled to the solute dynamics and is essential for the dynamics and functional properties of proteins.
|
|
| 14. |
- Goracci, G., et al.
(författare)
-
Dynamics of nano-confined water in Portland cement - comparison with synthetic C-S-H gel and other silicate materials
- 2017
-
Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322 .- 2045-2322. ; 7:1, s. Article no 8258-
-
Tidskriftsartikel (refereegranskat)abstract
- The dynamics of water confined in cement materials is still a matter of debate in spite of the fact that water has a major influence on properties such as durability and performance. In this study, we have investigated the dynamics of water confined in Portland cement (OPC) at different curing ages (3 weeks and 4 years after preparation) and at three water-to-cement ratios (w/c, 0.3, 0.4 and 0.5). Using broadband dielectric spectroscopy, we distinguish four different dynamics due to water molecules confined in the pores of different sizes of cements. Here we show how water dynamics is modified by the evolution in the microstructure (maturity) and the w/c ratio. The fastest dynamics (processes 1 and 2, representing very local water dynamics) are independent of water content and the degree of maturity whereas the slowest dynamics (processes 3 and 4) are dependent on the microstructure developed during curing. Additionally, we analyze the differences regarding the water dynamics when confined in synthetic C-S-H gel and in the C-S-H of Portland cement.
|
|
| 15. |
- McCallum, Erin S., et al.
(författare)
-
Cost-effective pharmaceutical implants in fish : validating the performance of slow-release implants for the antidepressant fluoxetine
- 2023
-
Ingår i: Environmental Toxicology and Chemistry. - : John Wiley & Sons. - 0730-7268 .- 1552-8618. ; 42:6, s. 1326-1336
-
Tidskriftsartikel (refereegranskat)abstract
- Internal, slow-release implants can be an effective way to manipulate animal physiology or deliver a chemical exposure over long periods of time without the need for an exogenous exposure route. Slow-release implants involve dissolving a compound in a lipid-based carrier, which is inserted into the body of an organism. However, the release kinetics of the compound from the implant to body tissues also requires careful validation. We tested and validated a slow-release implant methodology for exposing fish to a pharmaceutical pollutant, fluoxetine. We tested two lipid-based carriers (coconut oil or vegetable shortening) in the common roach (Rutilus rutilus). The implants contained either a high (50 μg/g), low (25 μg/g), or control (0 μg/g) concentration of fluoxetine, and we measured tissue uptake in the brain, muscle, and plasma of implanted fish over 25 days. The two carriers released fluoxetine differently over time: coconut oil released fluoxetine in an accelerating manner (tissue uptake displayed a positive quadratic curvature), whereas vegetable shortening released fluoxetine in a decelerating manner (a negative quadratic curvature). For both carrier types, fluoxetine was measured at the highest concentration in the brain, followed by muscle and plasma. By comparing the implant exposures with waterborne exposures in the published literature, we showed that the implants delivered an internal exposure that would be similar if fish were exposed in surface waters containing effluents. Overall, we showed that slow-release internal implants are an effective method for delivering chronic exposures of fluoxetine over at least 1-month time scales. Internal exposures can be an especially powerful experimental tool when coupled with field-based study designs to assess the impacts of pharmaceutical pollutants in complex natural environments. Environ Toxicol Chem 2023;00:1–10. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.
|
|
| 16. |
- Melillo, Jorge H., et al.
(författare)
-
Influence of ice formation on the dynamic and thermodynamic properties of aqueous solutions
- 2022
-
Ingår i: Journal of Molecular Liquids. - : Elsevier BV. - 0167-7322. ; 356
-
Tidskriftsartikel (refereegranskat)abstract
- Water dynamics in solutions with biological or non-biological solutes has been intensely studied when both components (solvent and solute) are amorphous. Here, we apply broadband dielectric spectroscopy combined with calorimetric measurements to analyze the dynamics of the aqueous solutions tri-propylene glycol (3PG) and ε-poly (lysine) (ε-PLL), after their water becomes semi-crystalline. Various crystallization levels were explored by conducting experiments with different annealing times at temperatures above the glass transition temperature (Tg). We find that the amount of ice depends on both the time and temperature of the annealing, and that this, in turn, affects Tg and dynamics of the amorphous part of the samples. However, it should be noted that the observed differences are relatively small for the degrees of crystallinity we have studied (up to about 26 wt% of the water). This also implies that the dynamic crossover of the water relaxation from a high temperature non-Arrhenius behavior to a low temperature Arrhenius dependence is unaffected by the partial crystallization and still occurs as a single crossover at the calorimetric Tg. Thus, we cannot detect two different crossovers, as commonly observed for other types of two-component systems, such as two glass formers.
|
|
| 17. |
- Rodrigues, João S., 1993-, et al.
(författare)
-
Characterizing isoprene production in cyanobacteria-Insights into the effects of light, temperature, and isoprene on Synechocystis sp. PCC 6803
- 2023
-
Ingår i: Bioresource Technology. - : Elsevier. - 0960-8524 .- 1873-2976. ; 380
-
Tidskriftsartikel (refereegranskat)abstract
- Engineering cyanobacteria for the production of isoprene and other terpenoids has gained increasing attention in the field of biotechnology. Several studies have addressed optimization of isoprene synthesis in cyanobacteria via enzyme and pathway engineering. However, only little attention has been paid to the optimization of cultivation conditions. In this study, an isoprene-producing strain of Synechocystis sp. PCC 6803 and two control strains were grown under a variety of cultivation conditions. Isoprene production, as quantified by modified membrane inlet mass spectrometer (MIMS) and interpreted using Flux Balance Analysis (FBA), increased under violet light and at elevated temperature. Increase of thermotolerance in the isoprene producer was attributed to the physical presence of isoprene, similar to plants. The results demonstrate a beneficial effect of isoprene on cell survival at higher temperatures. This increased thermotolerance opens new possibilities for sustainable bio-production of isoprene and other products.
|
|
| 18. |
- Swenson, Jan, 1966, et al.
(författare)
-
Dynamics of deeply supercooled interfacial water
- 2015
-
Ingår i: Journal of Physics Condensed Matter. - : IOP Publishing. - 0953-8984 .- 1361-648X. ; 27:3, s. Art. no. 033102-
-
Tidskriftsartikel (refereegranskat)abstract
- In this review we discuss the relaxation dynamics of glassy and deeply supercooled water in different types of systems. We compare the dynamics of such interfacial water in ordinary aqueous solutions, hard confinements and biological soft materials. In all these types of systems the dielectric relaxation time of the main water process exhibits a dynamic crossover from a high-temperature non-Arrhenius temperature dependence to a low-temperature Arrhenius behavior. Moreover, at large enough water content the low-temperature process is universal and exhibits the same temperature behavior in all types of systems. However, the physical nature of the dynamic crossover is somewhat different for the different types of systems. In ordinary aqueous solutions it is not even a proper dynamic crossover, since the water relaxation decouples from the cooperative alpha-relaxation of the solution slightly above the glass transition in the same way as all secondary (beta) relaxations of glass-forming materials. In hard confinements, the physical origin of the dynamic crossover is not fully clear, but it seems to occur when the cooperative main relaxation of water at high temperatures reaches a temperature where the volume required for its cooperative motion exceeds the size of the geometrically-confined water cluster. Due to this confinement effect the alpha-like main relaxation of the confined water seems to transform to a more local beta-relaxation with decreasing temperature. Since this low-temperature beta-relaxation is universal for all systems at high water content it is possible that it can be considered as an intrinsic beta-relaxation of supercooled water, including supercooled bulk water. This possibility, together with other findings for deeply supercooled interfacial water, suggests that the most accepted relaxation scenarios for supercooled bulk water have to be altered.
|
|
