Liquid polymorphism and density anomaly in a three-dimensional associating lattice gas

We investigate the phase diagram of a three-dimensional associating gas $(ALG)$ model. This model combines orientational ice-like interactions and ``van der Waals'' that might be repulsive, representing, in this case, a penalty for distortion of hydrogen bonds. These interactions can be interpreted as two competing distances making the connection between this model and continuous isotropic soft-core potentials. We present Monte Carlo studies of the $ALG$ model showing the presence of two liquid phase, two critical points and A density anomaly

Hydration and anomalous solubility of the Bell-Lavis model as solvent

We address the investigation of the solvation properties of the minimal orientational model for water, originally proposed by Bell and Lavis. The model presents two liquid phases separated by a critical line. The difference between the two phases is the presence of structure in the liquid of lower density, described through orientational order of particles. We have considered the effect of small inert solute on the solvent thermodynamic phases. Solute stabilizes the structure of solvent, by the organization of solvent particles around solute particles, at low temperatures. Thus, even at very high densities, the solution presents clusters of structured water particles surrounding solute inert particles, in a region in which pure solvent would be free of structure. Solute intercalates with solvent, a feature which has been suggested by experimental and atomistic simulation data. Examination of solute solubility has yielded a minimum in that property, which may be associated with the minimum found for noble gases. We have obtained a line of minimum solubility (TmS) across the phase diagram, accompanying the line of maximum in density (TMD). This coincidence is easily explained for non-interacting solute and it is in agreement with earlier results in the literature. We give a simple argument which suggests that interacting solute would dislocate TmS to higher temperatures

Bioaccessibility of lipophilic and hydrophilic marine biotoxins in seafood: An in vitro digestion approach

This study aimed to assess the bioaccessibility of different marine biotoxins in naturally contaminated shellfish and fish gonads using an in vitro digestion methodology. In general, hydrophilic toxins (domoic acid, paralytic shellfish poisoning toxins and tetrodotoxins) showed higher bioaccessibility than lipophilic ones (okadaic acid and azaspiracids). The bioaccessibility of toxins from the okadaic acid group ranged from 69% (raw European razor clams) to 74% (raw donax clams). Regarding azaspiracids, 47% of the initial content was bioaccessible in steamed blue mussel. As for hydrophilic toxins, 100% of the initial content was bioaccessible after digestion in raw shellfish and puffer fish gonads. The total tetrodotoxin bioaccessibility in puffer fish gonads decreased significantly after steaming. The profile of tetrodotoxins changed during the digestion process: TTX and 11-norTTX-6S-ol analogues decreased significantly after digestion, but the 5,6,11-trideoxy TTX analogue increased in both raw and steamed puffer fish gonads. These preliminary findings confirm the need to consider bioaccessibility data in future seafood risk assessment, as such information enables a more accurate and realistic estimation of potential seafood hazards, particularly in what concerns lipophilic toxins, therefore, constituting a crucial tool in the refinement of regulatory limits for the presence of biotoxins in seafood.info:eu-repo/semantics/acceptedVersio

Bioaccessibility of lipophilic and hydrophilic marine biotoxins in seafood: an in vitro digestion approach

This study aimed to assess the bioaccessibility of different marine biotoxins in naturally contaminated shellfish and fish gonads using an in vitro digestion methodology. In general, hydrophilic toxins (domoic acid, paralytic shellfish poisoning toxins and tetrodotoxins) showed higher bioaccessibility than lipophilic ones (okadaic acid and azaspiracids). The bioaccessibility of toxins from the okadaic acid group ranged from 69% (raw European razor clams) to 74% (raw donax clams). Regarding azaspiracids, 47% of the initial content was bioaccessible in steamed blue mussel. As for hydrophilic toxins, 100% of the initial content was bioaccessible after digestion in raw shellfish and puffer fish gonads. The total tetrodotoxin bioaccessibility in puffer fish gonads decreased significantly after steaming. The profile of tetrodotoxins changed during the digestion process: TTX and 11-norTTX-6S-ol analogues decreased significantly after digestion, but the 5,6,11-trideoxy TTX analogue increased in both raw and steamed puffer fish gonads. These preliminary findings confirm the need to consider bioaccessibility data in future seafood risk assessment, as such information enables a more accurate and realistic estimation of potential seafood hazards, particularly in what concerns lipophilic toxins, therefore, constituting a crucial tool in the refinement of regulatory limits for the presence of biotoxins in seafood.FCT - PD/BD/113484/2015info:eu-repo/semantics/publishedVersio

Structure and anomalous solubility for hard spheres in an associating lattice gas model

In this paper we investigate the solubility of a hard-sphere gas in a solvent modeled as an associating lattice gas. The solution phase diagram for solute at 5% is compared with the phase diagram of the original solute free model. Model properties are investigated both through Monte Carlo simulations and a cluster approximation. The model solubility is computed via simulations and is shown to exhibit a minimum as a function of temperature. The line of minimum solubility (TmS) coincides with the line of maximum density (TMD) for different solvent chemical potentials, in accordance with the literature on continuous realistic models and on the "cavity" picture. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4743635]Conselho Nacional de Pesquisas (CNPq)Conselho Nacional de Pesquisas (CNPq) [475039/2010-6, 472210/2011-4]CAPESCapesInstituto Nacional de Ciencia e Tecnologia de Fluidos Complexos (INCTFCx)Instituto Nacional de Ciencia e Tecnologia de FLUIDOS COMPLEXOS (INCT-FCx)Universidade Federal de Santa CatarinaUniversidade Federal de Santa Catarin

Occurrence of halogenated flame retardants in commercial seafood species available in European markets

PBDEs (congeners 28, 47, 99, 100, 153, 154, 183, 209), HBCD (α, β, γ), emerging brominated flame retardants (PBEB, HBB and DBDPE), dechloranes (Dec 602, 603, 604, syn- and anti-DP), TBBPA, 2,4,6-TBP and MeO-PBDEs (8 congeners) were analysed in commercial seafood samples from European countries. Levels were similar to literature and above the environmental quality standards (EQS) limit of the Directive 2013/39/EU for PBDEs. Contaminants were found in 90.5% of the seafood samples at n. d.-356 ng/g lw (n. d.-41.1 ng/g ww). DBDPE was not detected and 2,4,6-TBP was detected only in mussels, but at levels comparable to those of PBDEs. Mussel and seabream were the most contaminated species and the Mediterranean Sea (FAO Fishing Area 37) was the most contaminated location. The risk assessment revealed that there was no health risk related to the exposure to brominated flame retardants via seafood consumption. However, a refined risk assessment for BDE-99 is of interest in the future. Moreover, the cooking process concentrated PBDEs and HB

Microvascular damage assessed by optical coherence tomography angiography for glaucoma diagnosis: a systematic review of the most discriminative regions

A growing number of studies have reported a link between vascular damage and glaucoma based on optical coherence tomography angiography (OCTA) imaging. This multitude of studies focused on different regions of interest (ROIs) which offers the possibility to draw conclusions on the most discriminative locations to diagnose glaucoma. The objective of this work was to review and analyse the discriminative capacity of vascular density, retrieved from different ROIs, on differentiating healthy subjects from glaucoma patients. PubMed was used to perform a systematic review on the analysis of glaucomatous vascular damage using OCTA. All studies up to 21 April 2019 were considered. The ROIs were analysed by region (macula, optic disc and peripapillary region), layer (superficial and deep capillary plexus, avascular, whole retina, choriocapillaris and choroid) and sector (according to the Garway–Heath map). The area under receiver operator characteristic curve (AUROC) and the statistical difference (p-value) were used to report the importance of each ROI for diagnosing glaucoma. From 96 screened studies, 43 were eligible for this review. Overall, the peripapillary region showed to be the most discriminative region with the highest mean AUROC (0.80 ± 0.09). An improvement of the AUROC from this region is observed when a sectorial analysis is performed, with the highest AUROCs obtained at the inferior and superior sectors of the superficial capillary plexus in the peripapillary region (0.86 ± 0.03 and 0.87 ± 0.10, respectively). The presented work shows that glaucomatous vascular damage can be assessed using OCTA, and its added value as a complementary feature for glaucoma diagnosis depends on the region of interest. A sectorial analysis of the superficial layer at the peripapillary region is preferable for assessing glaucomatous vascular damage

Extreme and long-term drought in the La Plata Basin: event evolution and impact assessment until September 2022

The current drought conditions across the Parana-La Plata Basin (LPB) in Brazil-Argentina have been the worst since 1944. While this area is characterized by a rainy season with a peak from October to April, the hydrological year 2020-2021 was very deficient in rainfall, and the situation extended into the 2021-2022 hydrological year. Below-normal rainfall was dominant in south-eastern Brazil, northern Argentina, Paraguay, and Uruguay, suggesting a late onset and weaker South American Monsoon and the continuation of drier conditions since 2021. In fact, in 2021 Brazilian south and south-east regions faced their worst droughts in nine decades, raising the spectre of possible power rationing given the grid dependence on hydroelectric plants. The Paraná-La Plata Basin drought induced damages to agriculture and reduced crop production, including soybeans and maize, with effects on global crop markets. The drought situation continued in 2022 in the Pantanal region. Dry meteorological conditions are still present in the region at the end of September 2022 with below-average precipitation anomalies. Soil moisture anomaly and vegetation conditions are worst in the lower part of the La Plata Basin, in the southern regions. Conversely, upper and central part of the basin show partial and temporary recovery