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1.
Plants (Basel) ; 13(9)2024 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-38732427

RESUMO

The estimation of crop evapotranspiration (ETc) is crucial for irrigation water management, especially in arid regions. This can be particularly relevant in the Po Valley (Italy), where arable lands suffer from drought damages on an annual basis, causing drastic crop yield losses. This study presents a novel approach for vegetation-based estimation of crop evapotranspiration (ETc) for maize. Three years of high-resolution multispectral satellite (Sentinel-2)-based Normalized Difference Vegetation Index (NDVI), Normalized Difference Water Index (NDWI), Normalized Difference Red Edge Index (NDRE), and Leaf Area Index (LAI) time series data were used to derive crop coefficients of maize in nine plots at the Acqua Campus experimental farm of Irrigation Consortium for the Emilia Romagna Canal (CER), Italy. Since certain vegetation indices (VIs) (such as NDVI) have an exponential nature compared to the other indices, both linear and power regression models were evaluated to estimate the crop coefficient (Kc). In the context of linear regression, the correlations between Food and Agriculture Organization (FAO)-based Kc and NDWI, NDRE, NDVI, and LAI-based Kc were 0.833, 0.870, 0.886, and 0.771, respectively. Strong correlation values in the case of power regression (NDWI: 0.876, NDRE: 0.872, NDVI: 0.888, LAI: 0.746) indicated an alternative approach to provide crop coefficients for the vegetation period. The VI-based ETc values were calculated using reference evapotranspiration (ET0) and VI-based Kc. The weather station data of CER were used to calculate ET0 based on Penman-Monteith estimation. Out of the Vis, NDWI and NDVI-based ETc performed the best both in the cases of linear (NDWI RMSE: 0.43 ± 0.12; NDVI RMSE: 0.43 ± 0.095) and power (NDWI RMSE: 0.44 ± 0.116; NDVI RMSE: 0.44 ± 0.103) approaches. The findings affirm the efficacy of the developed methodology in accurately assessing the evapotranspiration rate. Consequently, it offers a more refined temporal estimation of water requirements for maize cultivation in the region.

2.
Heliyon ; 10(1): e23238, 2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-38163152

RESUMO

Microalgae cultivation could contribute to the achievement of several sustainable development goals (SDGs). However, cultivating Chlorella vulgaris, like any other microalgae, is challenging due to various biotic, abiotic and process related factors that can affect its growth and biomass productivity. Nutrient availability, particularly N and P, and their ratio play a crucial role in building cellular structures and maintaining metabolic processes, determining basically the maximum achievable biomass productivity under given circumstances. The present article aims to improve the N and P ratio to enhance the biomass productivity of Chlorella vulgaris microalgae as well as to characterize the biomass growth kinetics that can be used for prediction purposes. The results showed that the nutrient solutions prepared with increased nitrate concentration (T1 - N:P = 55:1 and T3 - N:P = 28:1) promoted chlorophyll formation and significantly outperformed the control sample (BG-11 - N:P = 35:1) with 192% and 183%, leading to higher biomass productivity with 1160 µg L-1 and 1103 µg L-1, respectively. Moreover, a strong positive correlation was revealed (0.81) between phosphate concentration and microalgae activity rate, indicating the role of phosphorous in energy transfer, resulted in stimulated microalgae activity rates with 71.2% and 70.66% in the phosphate-increased nutrient solutions (T2 - N:P = 14:1 and T3 - N:P = 28:1). In addition, an exponential equation was introduced to characterize the biomass growth kinetics, of which the theoretically achievable maximum chlorophyll concentration (CTAM) and the theoretical cultivation time (tcultivation) were determined for the tested nutrient solutions with variable N:P ratio. It was concluded, that the higher the N:P ratio, the higher the CTAM is, nevertheless the absolute concentration of these nutrients need to be considered as well. The introduced two key parameters could provide valuable information for decision makers regarding the optimization of growth conditions, nutrient supplementation, and harvesting, additionally decreasing the production costs and making the cultivation cycles more effective and sustainable.

3.
J Cardiovasc Electrophysiol ; 34(5): 1177-1182, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36942777

RESUMO

INTRODUCTION: Routine ultrasound (US) guidance for femoral venous access to decrease vascular complications of atrial fibrillation (AF) ablation procedures has been advocated. However, the benefit has not been unequivocally demonstrated by randomized-trial data. METHODS: Consecutive patients undergoing pulmonary vein isolation (PVI) on uninterrupted anticoagulant treatment were included. A quasi-random allocation to either US-guided or conventional puncture group was based on which of the two procedure rooms the patient was scheduled in, with only one of the rooms equipped with a US machine including a vascular transducer. The same four novice operators in rotation, with no relevant previous experience in US-guided vascular access performed venous punctures in both rooms. Major and minor vascular complications and the rate of prolonged hospitalization were compared. Major vascular complication was defined as groin hematoma, arteriovenous fistula, or pseudoaneurysm. Hematoma was considered as a major vascular complication if it met type 2 or higher Bleeding Academic Research Consortium criteria (requiring nonsurgical, medical intervention by a health care professional; leading to hospitalization or increased level of care, or prompting evacuation). RESULTS: Of the 457 patients 199 were allocated to the US-guided puncture group, while the conventional, palpation-based approach was performed in 258 cases. Compared with the conventional technique, US guidance reduced the rate of any vascular complication (11.63% vs. 2.01%, p < .0001), including both major (4.26% vs. 1.01%, p = .038) and minor (7.36% vs. 1.01%, p = .001) vascular complications. In addition, the rate of prolonged hospitalization was lower in the US-guided puncture group (5.04% vs. 1.01%, p = .032). CONCLUSION: The use of US for femoral vein puncture in patients undergoing PVI decreased the rate of both major and minor vascular complications. This quasi-randomized comparison strongly supports adapting routine use of US for AF ablation procedures.


Assuntos
Fibrilação Atrial , Veias Pulmonares , Humanos , Veias Pulmonares/diagnóstico por imagem , Veias Pulmonares/cirurgia , Ultrassonografia de Intervenção/métodos , Hemorragia/etiologia , Hemorragia/prevenção & controle , Hematoma , Fibrilação Atrial/diagnóstico por imagem , Fibrilação Atrial/cirurgia , Resultado do Tratamento
4.
Int J Phytoremediation ; 25(11): 1510-1523, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36734108

RESUMO

In phytostabilization, heavy metal-tolerant plants (e.g.,grasses) can be used to reduce the mobility of heavy metals in soils. The most important step in phytostabilization is the selection of the suitable plant species, in which growth and development can be supported by soil amendments. Sewage sludge compost could be a suitable additive, which provides nutrients for the plant species used for phytostabilization and contributes to an alternative solution for sewage sludge utilization. The aim of the study was to examine the potential of sewage sludge compost in phytostabilization for heavy metal contaminated matrices: identify the optimal ratio of sewage sludge compost to decrease phytotoxicity of the matrices, and assessment of feasible plant species for phytostabilization based on its bioaccumulation properties. In this research, perennial ryegrass (Lolium perenne), broad-leaved sorrel sorrel (Rumex acetosa), lettuce (Lactuca sativa) and cabbage (Brassica oleracea var. capitata) were used for phytotoxicity experiments as well as for testing sewage sludge compost amended phytostabilization of polluted flotation sludge and mine tailings. Sewage sludge compost increased the pH and electric conductivity of the matrices. High salt content and low acidity, altogether with heavy metals caused harmful physiological effects on plant species grown without any compost addition. In the root development test, as in the germination test, the application of 5% sewage sludge compost proved to be optimal. The lower translocation factors of broad-leaved sorrel and perennial ryegrass showed a higher rate of heavy metal accumulation in the roots. Perennial ryegrass, cabbage, and lettuce plant species reached their maximum biomass by adding 5% of sewage sludge compost. Based on the bioaccumulation, translocation and biomass properties, application of perennial ryegrass is recommended for phytostabilization of heavy metal contaminated sites. Furthermore, composted sewage sludge also had a significant effect on the reduction of heavy metal uptake by cabbage and lettuce, which highlights their role as indicator plants in ecotoxicological measurements.


The effects of sewage sludge compost added to the heavy metals contaminated flotation sludge and mine tailings (pH = 4.8) were examined. The applicability of broad-leaved sorrel and perennial ryegrass that can be found under natural conditions in the study area was assessed as a function of sewage sludge compost ratio for phytostabilization purposes. Moreover, ecotoxicological tests had been performed with cabbage and lettuce on sewage sludge compost + flotation sludge and mine tailings mixtures. Based on the results, it was proved that the phytostabilization is feasible with the investigated plant species by adding 5% of sewage sludge compost to the flotation sludge and mine tailings.


Assuntos
Compostagem , Lolium , Metais Pesados , Poluentes do Solo , Esgotos/química , Solo , Poluentes do Solo/análise , Biodegradação Ambiental , Plantas
5.
Water Sci Technol ; 81(7): 1507-1517, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32616702

RESUMO

The main point of this research is to assess the applicability of condensed molasses soluble (CMS), which is an organic by-product of lysine fermentation, as an environmentally friendly complexing agent in rhizofiltration of heavy metal contaminated acid mine drainage (AMD). First, the ecotoxicological properties (growth inhibition, seed germination) of CMS were examined with often applied indicator plant species such as duckweed (Lemna minor) and lettuce (Lactuca sativa) so as to define the possible applicable CMS concentration. Then the heavy metal accumulation and translocation properties of root accumulator plant species, i.e. common reed (Phragmites australis) and sedge (Carex flacca), were studied to optimize CMS concentration for rhizofiltration. Due to the CMS application, significant increase in bioaccumulation was detected in the case of every examined heavy metal (As, Cd, Cu, Pb and Zn) at the end of the experiment. Results also showed that CMS increased the heavy metal concentration in shoots, but did not affect the root accumulation characteristics of the plants. Furthermore, CMS treated plants accumulated heavy metals at higher rates in their roots compared to control. The results suggest that CMS is a viable additive and a complexing agent to aid rhizofiltration of heavy metal contaminated AMD.


Assuntos
Metais Pesados/análise , Poluentes do Solo/análise , Biodegradação Ambiental , Fermentação , Lisina , Mineração , Raízes de Plantas
6.
J Evol Biol ; 32(12): 1450-1455, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31604005

RESUMO

We published a study recently testing the link between brain size and behavioural plasticity using brain size selected guppy (Poecilia reticulata) lines (2019, Journal of Evolutionary Biology, 32, 218-226). Only large-brained fish showed habituation to a new, but actually harmless environment perceived as risky, by increasing movement activity over the 20-day observation period. We concluded that "Our results suggest that brain size likely explains some of the variation in behavioural plasticity found at the intraspecific level". In a commentary published in the same journal, Haave-Audet et al. challenged the main message of our study, stating that (a) relative brain size is not a suitable proxy for cognitive ability and (b) habituation measured by us is likely not adaptive and costly. In our response, we first show that a decade's work has proven repeatedly that relative brain size is indeed positively linked to cognitive performance in our model system. Second, we discuss how switching from stressed to unstressed behaviour in stressful situations without real risk is likely adaptive. Finally, we point out that the main cost of behavioural plasticity in our case is the development and maintenance of the neural system needed for information processing, and not the expression of plasticity. We hope that our discussion with Haave-Audet et al. helps clarifying some central issues in this emerging research field.


Assuntos
Poecilia , Animais , Encéfalo , Cognição , Movimento , Tamanho do Órgão
8.
Naturwissenschaften ; 106(3-4): 7, 2019 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-30729319

RESUMO

Most studies on animal personality evaluate individual mean behaviour to describe individual behavioural strategy, while often neglecting behavioural variability on the within-individual level. However, within-individual behavioural plasticity (variation induced by environment) and within-individual residual variation (regulatory behavioural precision) are recognized as biologically valid components of individual behaviour, but the evolutionary ecology of these components is still less understood. Here, we tested whether behaviour of common pill bugs (Armadillidium vulgare) differs on the among- and within-individual level and whether it is affected by various individual specific state-related traits (sex, size and Wolbachia infection). To this aim, we assayed risk-taking in familiar vs. unfamiliar environments 30 times along 38 days and applied double modelling statistical technique to handle the complex hierarchical structure for both individual-specific trait means and variances. We found that there are significant among-individual differences not only in mean risk-taking behaviour but also in environment- and time-induced behavioural plasticity and residual variation. Wolbachia-infected individuals took less risk than healthy conspecifics; in addition, individuals became more risk-averse with time. Residual variation decreased with time, and individuals expressed higher residual variation in the unfamiliar environment. Further, sensitization was stronger in females and in larger individuals in general. Our results suggest that among-individual variation, behavioural plasticity and residual variation are all (i) biologically relevant components of an individual's behavioural strategy and (ii) responsive to changes in environment or labile state variables. We propose pill bugs as promising models for personality research due to the relative ease of getting repeated behavioural measurements.


Assuntos
Comportamento Animal/fisiologia , Meio Ambiente , Isópodes/fisiologia , Animais , Isópodes/microbiologia , Modelos Animais , Wolbachia/fisiologia
9.
J Anim Ecol ; 87(5): 1264-1273, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29752882

RESUMO

Behavioural consistency within and across behaviours (animal personality and behavioural syndrome, respectively) has been vigorously studied in the last decade, leading to the emergence of "animal personality" research. It has been proposed recently that not only mean behaviour (behavioural type), but the environmentally induced behavioural change (behavioural plasticity) might also differ between individuals within populations. While case studies presenting between-individual variation in behavioural plasticity have started to accumulate, the mechanisms behind its emergence are virtually unknown. We have recently demonstrated that ecologically relevant environmental stimuli during ontogeny are necessary for the development of animal personality and behavioural syndromes. However, it is unknown whether between-individual variation in behavioural plasticity is hard-wired or induced. Here, we tested whether experience with predation during development affected predator-induced behavioural plasticity in Rana dalmatina tadpoles. We ran a common garden experiment with two ontogenetic predation treatments: tadpoles developed from hatching in either the presence or absence of olfactory predator stimuli. Then, we assayed all tadpoles repeatedly for activity and risk-taking both in the absence and presence of olfactory predator stimuli. We found that (a) between-individual variation in predator-induced behavioural plasticity was present only in the group that developed in the presence of olfactory stimuli from predators and (b) previous experience with predatory stimuli resulted in lower plastic response at the group level. The latter pattern resulted from increased between-individual variation and not from universally lower individual responses. We also found that experience with predation during development increased the predictability (i.e. decreased the within-individual variation unrelated to environmental change) of activity, but not risk-taking. In line with this, tadpoles developing under perceived predatory risk expressed their activity with higher repeatability. We suggest that ecologically relevant environmental stimuli are not only fundamental for the development of animal personality and behavioural syndromes, but also for individual variation in behavioural plasticity. Thus, experience is of central importance for the emergence of individual behavioural variation at many levels.


Assuntos
Comportamento Predatório , Ranidae , Animais , Larva , Personalidade
10.
PLoS One ; 12(11): e0187657, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29112964

RESUMO

Understanding the background mechanisms affecting the emergence and maintenance of consistent between-individual variation within population in single (animal personality) or across multiple (behavioural syndrome) behaviours has key importance. State-dependence theory suggests that behaviour is 'anchored' to individual state (e.g. body condition, gender, age) and behavioural consistency emerges through behavioural-state feedbacks. A number of relevant state variables are labile (e.g. body condition, physiological performance) and expected to be affected by short-term environmental change. Yet, whether short-term environmental shifts affect behavioural consistency during adulthood remains questionable. Here, by employing a full-factorial laboratory experiment, we explored if quantity of food (low vs. high) and time available for thermoregulation (3h vs. 10h per day) had an effect on activity and risk-taking of reproductive adult male European green lizards (Lacerta viridis). We focussed on different components of behavioural variation: (i) strength of behavioural consistency (repeatability for animal personality; between-individual correlation for behavioural syndrome), (ii) behavioural type (individual mean behaviour) and (iii) behavioural predictability (within-individual behavioural variation). Activity was repeatable in all treatments. Risk-taking was repeatable only in the low basking treatments. We found significant between-individual correlation only in the low food × long basking time group. The treatments did not affect behavioural type, but affected behavioural predictability. Activity predictability was higher in the short basking treatment, where it also decreased with size (≈ age). Risk-taking predictability in the short basking treatment increased with size under food limitation, but decreased when food supply was high. We conclude that short-term environmental change can alter various components of behavioural consistency. The effect could be detected in the presence/absence patterns of animal personality and behavioural syndrome and the level of individual behavioural predictability, but not in behavioural type.


Assuntos
Comportamento Animal , Meio Ambiente , Lagartos/fisiologia , Animais , Regulação da Temperatura Corporal , Masculino
11.
Int Urol Nephrol ; 48(2): 271-7, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26560477

RESUMO

AIM: The incidence of atrial fibrillation is increased during hemodialysis (HD); however, the effects of hemodiafiltration (HDF) on atrial arrhythmias have not been evaluated. The prolongation of the P wave and P dispersion (Pd) can predict atrial arrhythmias. METHODS: Data from 30 patients receiving HDF over a period of 3 months were collected; the same group of patients was then evaluated during treatment with conventional HD for at least another 3 months. Electrolyte values were obtained, and surface electrocardiograms (ECG), echocardiography, and Holter ECGs were performed. RESULTS: The duration of the P wave and Pd increased significantly during HD. The left atrial diameter decreased significantly only during HDF. During HDF, the left atrial cross diameter measured at the beginning of the session was positively correlated with the incidence of supraventricular premature beats (p = 0.011, r = 0.4556). The decrease in left atrial diameter during HDF was negatively correlated with the incidence of supraventricular premature beats (p = 0.016, r = -0.43). During HDF, the changes in sodium and Pd were significantly positively correlated (p < 0.05, r = 0.478). During HD, the changes in ionized calcium levels and Pd were positively correlated (p < 0.05, r = 0.377). CONCLUSION: Our results suggest that HDF has a more beneficial effect on P wave duration and Pd than HD. The alterations in the ECG markers may be the result of the simultaneous occurrence of certain electrolyte imbalances and renal replacement methods.


Assuntos
Fibrilação Atrial/etiologia , Eletrocardiografia , Hemodiafiltração/efeitos adversos , Falência Renal Crônica/terapia , Diálise Renal/efeitos adversos , Adulto , Idoso , Idoso de 80 Anos ou mais , Fibrilação Atrial/epidemiologia , Fibrilação Atrial/fisiopatologia , Feminino , Seguimentos , Humanos , Hungria/epidemiologia , Incidência , Falência Renal Crônica/fisiopatologia , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Taxa de Sobrevida/tendências , Fatores de Tempo , Adulto Jovem
12.
Water Sci Technol ; 72(12): 2212-20, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26676009

RESUMO

There is a close quality relationship between the harmful levels of all three drought indicator groups (meteorological, hydrological and agricultural). However, the numerical scale of the relationships between them is unclear and the conversion of indicators is unsolved. Different areas or an area with different forms of drought cannot be compared. For example, from the evaluation of meteorological drought using the standardized precipitation index (SPI) values of a river basin, it cannot be stated how many tonnes of maize will be lost during a given drought period. A reliable estimated rate of yield loss would be very important information for the planned interventions (i.e. by farmers or river basin management organisations) in terms of time and cost. The aim of our research project was to develop a process which could provide information for estimating relevant drought indexes and drought related yield losses more effectively from remotely sensed spectral data and to determine the congruency of data derived from spectral data and from field measurements. The paper discusses a new calculation method, which provides early information on physical implementation of drought risk levels. The elaborated method provides improvement in setting up a complex drought monitoring system, which could assist hydrologists, meteorologists and farmers to predict and more precisely quantify the yield loss and the role of vegetation in the hydrological cycle. The results also allow the conversion of different-purpose drought indices, such as meteorological, agricultural and hydrological ones, as well as allow more water-saving agricultural land use alternatives to be planned in the river basins.


Assuntos
Agricultura/métodos , Produtos Agrícolas/crescimento & desenvolvimento , Secas , Hidrologia/métodos , Meteorologia/métodos , Tecnologia de Sensoriamento Remoto/métodos , Biomassa , Calibragem , Europa (Continente) , Modelos Biológicos , Tecnologia de Sensoriamento Remoto/normas , Medição de Risco , Rios
13.
Oecologia ; 178(1): 129-40, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25656582

RESUMO

The focus of evolutionary behavioural ecologists has recently turned towards understanding the causes and consequences of behavioural consistency, manifesting either as animal personality (consistency in a single behaviour) or behavioural syndrome (consistency across more behaviours). Behavioural type (mean individual behaviour) has been linked to life-history strategies, leading to the emergence of the integrated pace-of-life syndrome (POLS) theory. Using Rana dalmatina tadpoles as models, we tested if behavioural consistency and POLS could be detected during the early ontogenesis of this amphibian. We targeted two ontogenetic stages and measured activity, exploration and risk-taking in a common garden experiment, assessing both individual behavioural type and intra-individual behavioural variation. We observed that activity was consistent in all tadpoles, exploration only became consistent with advancing age and risk-taking only became consistent in tadpoles that had been tested, and thus disturbed, earlier. Only previously tested tadpoles showed trends indicative of behavioural syndromes. We found an activity-age at metamorphosis POLS in the previously untested tadpoles irrespective of age. Relative growth rate correlated positively with the intra-individual variation of activity of the previously untested older tadpoles. In previously tested older tadpoles, intra-individual variation of exploration correlated negatively and intra-individual variation of risk-taking correlated positively with relative growth rate. We provide evidence for behavioural consistency and POLS in predator- and conspecific-naive tadpoles. Intra-individual behavioural variation was also correlated to life history, suggesting its relevance for the POLS theory. The strong effect of moderate disturbance related to standard behavioural testing on later behaviour draws attention to the pitfalls embedded in repeated testing.


Assuntos
Comportamento Animal , Larva , Metamorfose Biológica , Personalidade , Ranidae , Assunção de Riscos , Animais , Evolução Biológica , Larva/crescimento & desenvolvimento , Ranidae/crescimento & desenvolvimento
14.
Sci Total Environ ; 511: 423-34, 2015 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-25569578

RESUMO

The distribution and speciation of elements along a stream subjected to neutralised acid mine drainage (NAMD) effluent waters (Mátra Mountain, Hungary; Toka stream) were studied by a multi-methodological approach: dissolved and particulate fractions of elements were determined by HR-ICPMS, whereas speciation was carried out by DGT, supported by speciation modelling performed by Visual MINTEQ. Before the NAMD discharge, the Toka is considered as a pristine stream, with averages of dissolved concentrations of elements lower than world averages. A considerable increase of element concentrations caused by effluent water inflow is followed by a sharp or gradual concentration decrease. A large difference between total and dissolved concentrations was found for Fe, Al, Pb, Cu, Zn and As in effluent water and at the first downstream site, with high correlation factors between elements in particulate fraction, indicating their common behaviour, governed by the formation of ferri(hydr)oxides (co)precipitates. In-situ speciation by the DGT technique revealed that Zn, Cd, Ni, Co, Mn and U were predominantly present as a labile, potentially bioavailable fraction (>90%). The formation of strong complexes with dissolved organic matter (DOM) resulted in a relatively low DGT-labile concentration of Cu (42%), while low DGT-labile concentrations of Fe (5%) and Pb (12%) were presumably caused by their existence in colloidal (particulate) fraction which is not accessible to DGT. Except for Fe and Pb, a very good agreement between DGT-labile concentrations and those predicted by the applied speciation model was obtained, with an average correlation factor of 0.96. This study showed that the in-situ DGT technique in combination with model-predicted speciation and classical analysis of samples could provide a reasonable set of data for the assessment of the water quality status (WQS), as well as for the more general study of overall behaviour of the elements in natural waters subjected to high element loads.


Assuntos
Monitoramento Ambiental/métodos , Mineração , Modelos Químicos , Rios/química , Poluentes Químicos da Água/análise , Hungria
15.
Clin Exp Nephrol ; 18(6): 952-9, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24590361

RESUMO

BACKGROUND/AIMS: The prolongation of the QT interval and dispersion could predict ventricular arrhythmias. It is not yet established whether there is a difference between the effects of hemodialysis and hemodiafiltration on QT interval duration and dispersion. METHODS: Data of thirty patients was investigated while they were receiving hemodiafiltration over a period of 3 months; then the same group of patients was evaluated during treatment with conventional hemodialysis for at least another 3 months. Ionic parameters and surface electrocardiograms (ECG) were analyzed five times during each session, and 2D, M-mode echocardiography and Holter ECGs were performed to acquire additional information. RESULTS: QT interval duration (QTmax) and dispersion (QTd) showed a significant increase during hemodialysis, but not during hemodiafiltration. QTmax was 388.66 ± 31.81 ms at the beginning of hemodialysis and increased to 400.66 ± 39.12 ms even at the 30th minute (p < 0.05). QTd was found to be 31.33 ± 10.08 ms before the commencement of hemodialysis with the largest prolongation being seen at the 240th minute (51.33 ± 14.56 ms, p < 0.05). The occurrence of ventricular premature beats was significantly higher during hemodialysis (p = 0.018). The left atrial diameter significantly decreased at the end of hemodiafiltration (at the beginning 45.1 ± 5.25 mm, at the end 40.77 ± 5.76 mm; p < 0.05). CONCLUSION: Our results suggest a beneficial effect of hemodiafiltration on the studied electrocardiographic parameters compared to hemodialysis. The larger decrease in the left atrial diameter suggests a more efficient intracardiac volume-decreasing potential of hemodiafiltration.


Assuntos
Arritmias Cardíacas/epidemiologia , Eletrocardiografia , Hemodiafiltração/métodos , Falência Renal Crônica/terapia , Diálise Renal/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Arritmias Cardíacas/diagnóstico , Arritmias Cardíacas/fisiopatologia , Ecocardiografia , Feminino , Átrios do Coração/diagnóstico por imagem , Humanos , Falência Renal Crônica/fisiopatologia , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Fatores de Risco , Fatores de Tempo
16.
Environ Pollut ; 141(2): 310-20, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-16219405

RESUMO

Among the inorganic toxicants of greatest concern in mine tailings, Pb, Zn, Cu, Cd and As figure prominently due to their abundance and potential toxicity. Here we report on their biolability and solid-phase speciation in two sediment cores subject to variable hydrological regimes at an abandoned pyritic mine tailing. The oxic conditions of well-drained sediments induced pyrite oxidation and the subsequent liberation of H+, SO4(2-) and considerable quantities of Fe(III), which precipitated as goethite. Solubility of Pb, Zn, Cu and Cd was closely coupled to pH and goethite presence. Metal lability was particularly low in zones of neutralization, formed by the accumulation of calcite, first carried then deposited by percolating waters in both saturated and unsaturated cores. We conclude that differential hydrology induces variable heavy metal speciation and biolability in Pb-Zn mine tailings, and suggest that site-specific risk assessments must account for past and present hydrological regimes.


Assuntos
Poluentes Ambientais/análise , Sedimentos Geológicos/análise , Metais Pesados/análise , Mineração , Água/química , Disponibilidade Biológica , Cádmio/análise , Carbonato de Cálcio/análise , Cobre/análise , Condutividade Elétrica , Concentração de Íons de Hidrogênio , Ferro/análise , Compostos de Ferro/análise , Chumbo/análise , Minerais , Oxirredução , Tamanho da Partícula , Solubilidade , Sulfetos , Zinco/análise
17.
Z Naturforsch C J Biosci ; 60(3-4): 362-7, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-15948607

RESUMO

Vegetation at an abandoned heavy metal bearing mine tailing may have multifunctional roles such as modification of water balance, erosion control and landscape rehabilitation. Research on the vegetation of mine tailings can provide useful information on tolerance, accumulation and translocation properties of species potentially applicable at moderately contaminated sites. Analyses of the relationship between heavy metal content (Pb, Zn and Cu) and vegetation in a mine tailing were carried out. These analyses included: (1) spatial analysis of relationship among heavy metal distribution, pH and vegetation patterns, and (2) analysis of heavy metal accumulation and translocation in some plant species. Presence of vegetation was found to be significantly dependent on pH value, which confirms that phytotoxicity is a function of element concentration in solution, which is primarily controlled by pH value in mine tailings. Among the most abundant plant species, dewberry (Rubus caesius), vipersbugloss (Echium vulgare), scarlet pimpernel (Anagallis arvensis) and narrowleaf plantain (Plantago lanceolata) accumulate significant amounts of Pb, Cu and Zn, while in the case of annual bluegrass (Poa annua) only Pb can be measured in elevated contents. Considering the translocation features, scarlet pimpernel, narrowleaf plantain, and dewberry accumulate heavy metals primarily in their roots, while heavy metal concentration in vipersbugloss and annual bluegrass is higher in the shoots.


Assuntos
Metais Pesados/análise , Mineração , Plantas/metabolismo , Poluentes do Solo/análise , Cobre/farmacocinética , Hungria , Chumbo/farmacocinética , Desenvolvimento Vegetal , Fenômenos Fisiológicos Vegetais , Zinco/farmacocinética
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