The hydrogeological processes driving the hydrochemical composition of groundwater in the alpine pristine aquifer system of the Port del Comte Massif (PCM) are characterized through the multivariate ...statistical techniques Principal Component Analysis (PCA) and Gaussian Mixture Models (GMM) in the framework of Compositional Data (CoDa) analysis. Also, the groundwater Natural Background Levels (NBLs) for NO3 and SO4 and Cl are evaluated, which are specially important for indicating the occurrence of groundwater contamination derived from the anthropic activities conducted in the PCM.
The different hydrogeochemical facies found in the aquifer system of the PCM comprises low mineralized Ca-HCO3 water for the main Eocene karst aquifer, and Ca-SO4 and highly mineralized NaCl water types in the minor aquifers discharging from the PCM. The NBL values of SO4, Cl and NO3 obtained for the main karst aquifer are 14.33, 4.06 and 6.55 mg/L, respectively. These values are 35, 3 and 1.2 times lower than the respective official NBLs values that were determined by the water administration to be compared with in the case of conducting a pollution assessment characterization in the main karst aquifer. Official overestimation of NBLs can put important groundwater resources in the PCM at risk.
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•The Gaussian Mixture Models are used to cluster springs by hydrochemical response.•The clustering analysis groups the springs of the aquifer system into four families.•The compositional analysis approach is required for hydrochemical data analysis.•The hydrogeological characterization of Port del Compte Aquifer system is presented.•Natural base levels of nitrate and sulphate in the Port del Compte Aquifers are given.
Estimated natural background levels (NBLs) are needed to assess groundwater chemical status according to the EU Groundwater Directive. They are commonly derived for different substances by applying ...statistical methodologies. Due to the complexity of the sea water intrusion process, some of those methods do not always provide appropriate assessment of chloride NBLs. This paper analyzes the applicability of different NBL estimation methods in five EU coastal aquifers with significant differences in available datasets and hydrogeological settings. A sensitivity analysis of results to different constraints was performed to remove samples with anthropogenic impacts. A novel statistical approach combining different methods to identify the range of chloride NBLs is proposed. In all pilots the estimated NBLs were below 85 mg/L and fitted well with previous studies and expert judgment, except Campina del Faro aquifer (the maximum being 167.5 mg/L). Although this approach is more time consuming, it provides a more robust solution.
•Natural background levels (NBL) is used for assessing groundwater chemical status.•Estimating Cl-NBL is difficult due to the complexity of sea water intrusion process.•Existing statistical approaches & hypothesis to assess Cl- NBL are not always valid.•A novel statistical approach to identify range of Cl- NBL is proposed and tested.•The solution provides more robust results in coastal aquifers across Europe.
Water resources in high mountain karst aquifers are usually characterized by high rainfall, recharge and discharge that lead to the sustainability of the downstream ecosystems. Nevertheless, these ...hydrological systems are vulnerable to the global change impact. The mean transit time (MTT) is a key parameter to describe the behavior of these hydrologic systems and also to assess their vulnerability. This work is focused on estimating MTT by using environmental tracers in the framework of high-mountain karst systems with a very thick unsaturated zone (USZ). To this end, it is adapted to alpine zones a methodology that combines a semi-distributed rainfall-runoff model to estimate recharge time series, and a lumped-parameter model to obtain ΜΤΤ. The methodology has been applied to the Port del Comte Massif (PCM) hydrological system (Southeastern Pyrenees, NE Spain), a karst aquifer system with an overlying 1000 m thick USZ. Six catchment areas corresponding to most important springs of the system are considered. The obtained results show that hydrologically the behavior of the system can be described by an exponential flow model (EM), with MTT ranging between 1.9 and 2.9 years. These ΜΤΤ values are shorter than those obtained by considering a constant recharge rate along time, which is the easiest and most applied aquifer recharge hypothesis when estimating ΜΤΤ through lumped-parameter models.
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•Amplitude of seasonal isotopic composition of rainfall depends on elevation.•Moisture generating rainfall in the study zone comes from the Mediterranean.•The aquifer main recharge zones located at elevations between 2050 and 2387 m a.s.l•Considering transient recharge improves the estimations of mean transit times.•Transit times in agreement with the karstic nature of the aquifer system
Interest in attributing the risk of damaging weather-related events to anthropogenic climate change is increasing. Yet climate models used to study the attribution problem typically do not resolve ...the weather systems associated with damaging events such as the UK floods of October and November 2000. Occurring during the wettest autumn in England and Wales since records began in 1766, these floods damaged nearly 10,000 properties across that region, disrupted services severely, and caused insured losses estimated at £1.3 billion (refs 5, 6). Although the flooding was deemed a 'wake-up call' to the impacts of climate change at the time, such claims are typically supported only by general thermodynamic arguments that suggest increased extreme precipitation under global warming, but fail to account fully for the complex hydrometeorology associated with flooding. Here we present a multi-step, physically based 'probabilistic event attribution' framework showing that it is very likely that global anthropogenic greenhouse gas emissions substantially increased the risk of flood occurrence in England and Wales in autumn 2000. Using publicly volunteered distributed computing, we generate several thousand seasonal-forecast-resolution climate model simulations of autumn 2000 weather, both under realistic conditions, and under conditions as they might have been had these greenhouse gas emissions and the resulting large-scale warming never occurred. Results are fed into a precipitation-runoff model that is used to simulate severe daily river runoff events in England and Wales (proxy indicators of flood events). The precise magnitude of the anthropogenic contribution remains uncertain, but in nine out of ten cases our model results indicate that twentieth-century anthropogenic greenhouse gas emissions increased the risk of floods occurring in England and Wales in autumn 2000 by more than 20%, and in two out of three cases by more than 90%.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
This review provides a practical guide to myeloperoxidase (MPO) and presents to the reader the diversity of its presence in biology. The review provides a historical background, from peroxidase ...activity to the discovery of MPO, to its role in disease and drug development. MPO is discussed in terms of its necessity, as specific individuals lack MPO expression. An underlying theme presented throughout brings up the question of the benefit and burden of MPO activity. Enzyme structure is discussed, including accurate masses and glycosylation sites. The catalytic cycle of MPO and its corresponding pathways are presented, with a discussion of the importance of the redox couples of the different states of MPO. Cell lines expressing MPO are discussed and practically summarized for the reader, and locations of MPO (primary and secondary) are provided. Useful methods of MPO detection are discussed, and how these can be used for studying disease processes are implied through the presentation of MPO as a biomarker. The presence of MPO in neutrophil extracellular traps is presented, and the activators of the former are provided. Lastly, the transition from drug metabolism to a target for drug development is where the review concludes.
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•Myeloperoxidase (MPO) is an enzyme with remarkable diversity in health and disease.•MPO levels usually correlate with disease severity and is a key biomarker.•MPO has roles in COVID-19, drug oxidation, & neutrophil extracellular traps.•Clinical MPO inhibitors require further study to elucidate protective activity.
Proteins play a crucial role in determining texture and structure of many food products. Although some animal proteins (such as egg white) have excellent functional and organoleptic properties, ...unfortunately, they entail a higher production cost and environmental impact than plant proteins. It is rather unfortunate that plant protein functionality is often insufficient because of low solubility in aqueous media. Enzymatic hydrolysis strongly increases solubility of proteins and alters their functional properties. The latter is attributed to 3 major structural changes: a decrease in average molecular mass, a higher availability of hydrophobic regions, and the liberation of ionizable groups. We here review current knowledge on solubility, water‐ and fat‐holding capacity, gelation, foaming, and emulsifying properties of plant protein hydrolysates and discuss how these properties are affected by controlled enzymatic hydrolysis. In many cases, research in this field has been limited to fairly simple set‐ups where functionality has been assessed in model systems. To evolve toward a more widely applied industrial use of plant protein hydrolysates, a more thorough understanding of functional properties is required. The structure–function relationship of protein hydrolysates needs to be studied in depth. Finally, test model systems closer to real food processing conditions, and thus to real foods, would be helpful to evaluate whether plant protein hydrolysates could be a viable alternative for other functional protein sources.
The space‐time structure of flood losses is arguably related to large‐scale climatic patterns; however, this interconnection is not always well understood. Here we show that the North Atlantic ...Oscillation (NAO) correlates with the occurrence of catastrophic floods across Europe and the associated economic losses. The analysis reveals that in Northern Europe the majority of historic winter floods occurred during a positive NAO state, whereas the majority of summer floods occurred during a negative state. Analogous, but stronger, patterns can be observed in individual Atlantic countries. Through the application of a state‐of‐the‐art catastrophe model, we find that there is a statistically significant relationship between the NAO and flood losses. Critically, we observe that the average flood loss during opposite NAO states can differ by up to 50%. These results can inform financial preparedness and disaster fund allocation, as stakeholders, such as governments and insurance companies, can distribute resources more effectively.
Plain Language Summary
Increasing flood exposure and alarming climate change scenarios are responsible for growing concerns about economic losses from future floods. While it is well known that large‐scale climatic patterns control meteorological events, it is not always clear whether this connection can be extended to the occurrence of flood events and the associated losses. In this study, based on the analysis of recent flood databases and the application of a catastrophe model, we show that there is indeed a significant relationship between the North Atlantic Oscillation (NAO) and flood losses. The use of a model allows to quantify the impact of the NAO on flood losses and to show that average flood losses vary significantly across opposite NAO states. The study shows that the NAO index constitutes a meaningful predictor for long‐term average losses. In particular, based on recent development in NAO predictability, we argue that temporal variability of flood risk, due to climatic oscillations, can be predicted in advance, allowing for mitigation measures to take place sooner and enhance resiliency to flood hazard.
Key Points
Data reveal that there is a significant relationship between the NAO and the occurrence of catastrophic flood events in Europe
Model applications show that the NAO fluctuation has a significant impact on flood economic losses in Europe
Stakeholders should consider the impact of the NAO when planning disaster fund allocation and mitigation measures for flood risk in Europe
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•Aqueous extracts were made from flour of wheats grown at 0, 150 or 300 kg N/ha.•Protein and glucose-based oligomers/polymers were the main extract constituents.•The majority (60 to ...70%) of the extract proteins were α- and γ-gliadins.•N fertilization improved the stability of foams from aqueous wheat flour extracts.•α- and γ-gliadins were enriched in the extract foam fractions.
Aqueous phase extractable proteins from wheat can play a functional role in foods requiring interfacial stabilization. We here investigated the (protein) composition of aqueous flour extracts from wheats grown at different nitrogen (N) fertilization levels and studied their air–water interfacial characteristics. An important finding was that α- and γ-gliadins were extracted from wheat flour with water, even to an extent that they in the present work comprised 62–71% of the extract proteins. Application of N fertilization during wheat cultivation led to flour extracts with higher foam stabilities and air–water interface dilatational moduli. In all cases, proteins were found to most likely be the dominant constituent at the air–water interface. Analysis of foam protein compositions revealed an enrichment of proteins with molecular weights matching those of α- and γ-gliadins. It thus seems that gliadins can to a large extent determine the foaming characteristics of aqueous wheat flour extracts.
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•The soy protein isolate (SPI) production process was systematically investigated.•Hexane defatting of soy flour has no impact on its protein thermal properties.•Alkaline extraction ...has no impact on soy protein physical properties or composition.•SPI precipitated at pH 5.5 had highest protein solubility and lowest 7S/11S ratio.•SPI solutions contain a considerable amount of aggregated protein structures.
The functional properties of soy protein isolates (SPIs), which are crucial for their successful use in food applications, depend on their protein physical properties and composition. Although the production process of SPIs is well-known and established industrial practice, fundamental knowledge on how the different isolation steps and varying isolation conditions influence these properties is lacking. Here, these characteristics were systematically investigated by assessing the impacts of the various steps of a conventional isoelectric precipitation based SPI production protocol. Protein denaturation and colloidal state were evaluated with differential scanning calorimetry and dynamic light scattering combined with (ultra)centrifugation, respectively. The protein composition (on protein subunit level) was assessed via size-exclusion chromatography. Hexane defatting was found not to cause protein denaturation. Alkaline extraction at pH values between 7.0 and 9.0 resulted in no differences in protein physical properties or composition. Subsequent acid precipitation at pH 5.5 resulted in SPIs with a lower 7S/11S ratio and higher protein solubility at neutral pH than when produced at pH 4.5 and 3.5. SPIs obtained at all evaluated precipitation pH values contained a considerable amount of aggregated protein structures. Spray-drying of SPI did not result in a higher degree of protein denaturation or in a loss of protein solubility compared to freeze-drying, but a smaller amount of soluble aggregates was observed in spray-dried SPIs. Hence, alterations in the isolation procedure can result in SPIs with moderately different physical properties and protein composition, which might lead to different functional properties and thus applicabilities in certain food systems.
High-intensity ultrasonication is an emerging technology for plant protein isolation and modification. In this study, the potential of temperature-controlled ultrasonication to enhance the recovery ...of functional proteins from potato trimmings was assessed. Different ultrasound energy levels 2000–40,000 J/g fresh weight (FW) were applied during protein extraction at pH 9.0. True protein yields after ultrasonication significantly increased (up to 91%) compared to conventional extraction (33%). Microstructural analysis of the extraction residues showed more disrupted cells as ultrasonication time increased. Ultrasound treatments (10,000 and 20,000 J/g FW) increased the protein yield without affecting the foaming and air-water interfacial properties of protein isolates obtained after isoelectric precipitation (pH 4.0). However, proteins obtained after extended ultrasonication (40,000 J/g FW) had significantly slower early-stage adsorption kinetics. This was attributed to ultrasound-induced aggregation of the protease inhibitor fraction. In conclusion, ultrasonication shows potential to help overcome some challenges associated with plant protein extraction.
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•Ultrasonication significantly increases the protein recovery from potato trimmings.•Temperature-controlled ultrasonication causes disruption of cellular structures.•The impact on the foaming properties of the isolated proteins is limited.•Potato protease inhibitors aggregate during extended ultrasonication.•Interfacial adsorption of isolated proteins is slower after extended ultrasonication.
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