974 resultados para Chemical and biological parameters


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In this paper we investigated, for two years and with a bi-monthly frequency, how physical, chemical, and biological processes affect the marine carbonate system in a coastal area characterized by high alkalinity riverine discharge (Gulf of Trieste, northern Adriatic Sea, Mediterranean Sea).

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The physical and biological carbon pumps in the different hydrographic and biogeochemical regimes of the Atlantic Sector of the Southern Ocean are controlled by a series of coupled physical, chemical and biological processes and a project named Eddy-Pump was designed to study them. The Eddy Pump field campaign was carried out during RV Polarstern Cruise ANT-XXVIII/3 between January and March 2012. Particular emphasis was laid on the differences which occur along the axis of the Antarctic Circumpolar Current (ACC) with its associated mesoscale eddy field. The study sites were selected in order to represent (1) the central ACC with its regular separation in different frontal jets, investigated by a meridional transect along 10°E; (2) a large-scale bloom west of the Mid-Atlantic Ridge which lasted several months with conspicuous chlorophyll-poor waters to its immediate east studied by a three-dimensional mesoscale survey centred at 12°40'W; and (3) the Georgia Basin north of the island of South Georgia, which regularly features an extended and dense phytoplankton bloom, was investigated by a mesoscale survey centred at 38°12'W. While Eddy-Pump represents an interdisciplinary project by design, we here focus on describing the variable physical environment within which the different biogeochemical regimes developed. For describing the physical environment we use measurements of temperature, salinity and density, of mixed-layer turbulence parameters, of dynamic heights and horizontal current vectors, and of flow trajectories obtained from surface drifters and submerged floats. This serves as background information for the analyses of biological and chemical processes and of biogeochemical fluxes addressed by other papers in this issue. The section along 10°E between 44°S and 53°S showed a classical ACC structure with well-known hydrographic fronts, the Subantarctic Front (SAF) at 46.5°S, the Antarctic Polar Front (APF) split in two, at 49.25°S and 50.5°S, and the Southern Polar Front (SPF) at 52.5°S. Each front was associated with strong eastward flows. The West Mid-Atlantic Ridge Survey showed a weak and poorly resolved meander structure between the APF and the SPF. During the first eight days of the survey the oceanographic conditions at the Central Station at 12°40'W remained reasonably constant. However after that, conditions became more variable in the thermocline with conspicuous temperature inversions and interleavings and also a decrease in temperature in the surface layer. At the very end of the period of observation the conditions in the thermocline returned to being similar to those observed during the early part of the period with however the mixed layer temperature raised. The period of enhanced thermohaline variability was accompanied by increased currents. The Georgia Basin Survey showed a very strong zonal jet at its northern edge which connects to a large cyclonic meander that itself joins an anticyclonic eddy in the southeastern quadrant. The water mass contrasts in this survey were stronger than in the West Mid-Atlantic Ridge Survey, but similar to those met along 10°E with the exception that the warm and saline surface water typical of the northern side of the SAF was not covered by the Georgia Basin Survey. Mixed layers found during Eddy-Pump were typically deep, but varied between the three survey areas; the mean depths and standard variations of the mixed layer along the 10°E were 77.2±24.7 m, at the West Mid-Atlantic Ridge 66.7±17.7 m, and in the Georgia Basin 36.8±10.7 m.

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As discussed in Part I, a large accumulation of mammalian faeces at the mire site in the upper Guil Valley near Mt. Viso, dated to 2168cal 14C yr., provides the first evidence of the passage of substantial but indeterminate numbers of mammals within the time frame of the Punic invasion of Italia. Specialized organic biomarkers bound up in a highly convoluted and bioturbated bed constitute an unusual anomaly in a histosol comprised of fibric and hemist horizons that are usually expected to display horizontal bedding. The presence of deoxycholic acid and ethylcoprostanol derived from faecal matter, coupled with high relative numbers of Clostridia 16S rRNA genes, suggests a substantial accumulation of mammalian faeces at the site over 2000years ago. The results reported here constitute the first chemical and biological evidence of the passage of large numbers of mammals, possibly indicating the route of the Hannibalic army at this time. Combined with the geological analysis reported in Part I, these data provide a background supporting the need for further historical archaeological exploration in this area.

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Lake Albert/Mobutu lies along the Zaire-Uganda border in 43/57 per cent ratio in the faulted depression tending south-west to the north east. It is bounded by latitudes 1o0 n to 2o 20’ N and longitudes 30o 20’ to 31o 20’E. It has a width varying from 35 to 45 km (22 to 28 miles) as measured between the scarps at the lake level. It covers an area of 5600km2 and has a maximum depth of 48m. The major inflow is through the Semiliki, an outflow of Lake Edward, Muzizi and Victoria Nile draining lakes Victoria and Kyoga while the Albert Nile is the outflow. The physical, chemical and biological productivity parameters are summarized in Table 1. The scarp is steep but not sheer and there are at least 4 tracks leading down it to villages on the shore and scarp land scarp is a young one, formed as a result of earth movements of the Pleistocene times, and the numerous streams come down headlong down its thousand feet drop, more often than not in falls (Baker, 1954). Sometimes there appears to be a clean fault; and at other places there is the appearrence of step faulting, although this may be of only a superical nature .The escarpment’s composed of rocks belonging to the pre-Cambrian Basement complex of the content; but the floor of the depression is covered with young sedimentary rocks, known as kaiso beds. In their upper part these latter beds contains many pebbles; whilst low down the occurrence fossiliferous beds is sufficiently rare phenomenon in the interior plateau of Africa. The kaiso beds dated as possibly middle Pleistocene in age, are exposed in various flats on the shore, and they presumably extend under the relatively shallow waters of the lake. A feature of the shore is the development of sandpits and the enclosure of lagoons; and these can be observed in various stages of development at kaiso, Tonya, kibiro, Buhuka and above all, at Butiaba. On an island lake over 1100 km (700 miles) from the shores of the Indian Ocean one can thus study some of the shore-line phenomena usually associated with the sea- coast (Worthington, 1929). In the north, from Butiaba onwards, the flats become wider and from a continuous lowland as the lake shore curves away from the straight edge of the escarpment. At a height of just 610m (2000 feet) above sea-level, the rift valley floor at Butiaba has a mean annual temperature of 25.60c (780 f), from which there is virtually no seasonal variation; and and the mean daily range is only 6.50c (130f) (E.Afr. met. Dept.1953). With a mean annual rainfall of not much more than 762mm (309 inches) and only 92 rain days in ayear, again to judge from Butiaba, conditions in the rift valley are semi-arid; and the vegetation cover consists of grasses and scattered drought-resisting trees and bushes. Only near the stream courses does the vegetation thicken.

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Many maritime countries in Europe have implemented marine environmental monitoring programmes which include the measurement of chemical contaminants and related biological effects. How best to integrate data obtained in these two types of monitoring into meaningful assessments has been the subject of recent efforts by the International Council for Exploration of the Sea (ICES) Expert Groups. Work within these groups has concentrated on defining a core set of chemical and biological endpoints that can be used across maritime areas, defining confounding factors, supporting parameters and protocols for measurement. The framework comprised markers for concentrations of, exposure to and effects from, contaminants. Most importantly, assessment criteria for biological effect measurements have been set and the framework suggests how these measurements can be used in an integrated manner alongside contaminant measurements in biota, sediments and potentially water. Output from this process resulted in OSPAR Commission (www.ospar.org) guidelines that were adopted in 2012 on a trial basis for a period of 3 years. The developed assessment framework can furthermore provide a suitable approach for the assessment of Good Environmental Status (GES) for Descriptor 8 of the European Union (EU) Marine Strategy Framework Directive (MSFD).

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Boletus edulis Bull: Fr. is an edible mushroom quite appreciated for its organoleptic and nutritional properties. However, the seasonality and perishability cause some difficulties in its distribution and marketing in fresh form; losses associated with this type of food during marketing can reach 40% [1]. Irradiation is recognized as a safe and effective method for food preservation, being used worldwide to increase shelf life of fresh and dehydrated products (e.g. fruits, vegetables and spices) [2]. In particular, gamma irradiation has already been applied to cultivated mushrooms (especially Agaricus, Lentinula and Pleurotus Genus) and proved to be an interesting conservation technology [3]. However, the studies with added-value wild species are scarce. In this work, the effects of gamma irradiation on chemical and antioxidant properties of wild B. edulis, were evaluated. Fruiting bodies were obtained in Trás-os-Montes, in the Northeast of Portugal, in November 2012. The irradiation was performed in experimental equipment with 60Co sources at 1 and 2 kGy. All the results were compared with nonirradiated samples (control). Macronutrients and energy value were determined following official procedures of food analysis; fatty acids were analyzed by gas-chromatography coupled to flame ionization detection (GC-FID), while sugars and tocopherols were determined by high performance liquid chromatography (HPLC) coupled to refraction index (RI) and fluorescence detectors, respectively. Antioxidant activity was evaluated in the methanolic extracts by in vitro assays measuring DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity, reducing power, inhibition of β- carotene bleaching and inhibition of lipid peroxidation using thiobarbituric acid reactive substances (TBARS) assay. Total phenolics were also determined by the Folin-Ciocalteu assay. The nutritional profiles were not affected in high extension. Fatty acids and sugars were slightly affected, decreasing with the increasing doses. The performed assays for antioxidant activity, indicate that irradiated samples tended to have lower scavenging activity and reducing power, but higher lipid peroxidation inhibition. Despite the detected differences in individual compounds, the results of nutritional parameters, the most relevant in terms of mushroom acceptability by consumers, were less affected, indicating an interesting potential of gamma-irradiation to be used as an effective conservation technology for the studied mushrooms.

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Snake venom proteins from the C-type lectin family have very distinct biological activities despite their highly conserved primary structure, which is homologous to the carbohydrate recognition region of true C-type lectins. We purified a lectin-like protein (BmLec) from Bothrops moojeni venom and investigated its effect on platelet aggregation, insulin secretion, antibacterial activity, and isolated kidney cells. The BmLec was purified using two chromatographic steps: affinity chromatography and reverse phase high performance liquid chromatography (HPLC). BmLec showed a dose-dependent platelet aggregation and significantly decreased the bacterial growth rate in approximately 15%. During scanning electron microscopy, the profile of Xanthomonas axonopodis pv. passiflorae treated with lectin disclosed a high vesiculation and membrane rupture. BmLec induced a strong and significant increase in insulin secretion at 2.8 and 16.7 mM glucose concentrations, and this effect was seen in the presence of EGTA in both experiments. BmLec (10 mu g/mL) increased the perfusion pressure, renal vascular resistance and urinary flow. The glomerular filtration rate and percentages of sodium, potassium and chloride tubular transport were reduced at 60 minutes of perfusion. Renal alterations caused by BmLec were completely inhibited by indomethacin in all evaluated parameters. In conclusion, the C-type lectin isolated from Bothrops moojeni affected platelet aggregation, insulin secretion, antibacterial activity and isolated kidney function.

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Kiwi fruit is a highly nutritional fruit due to the high level of vitamin C and its strong antioxidant capacity due to a wide number of phytonutrients including carotenoids, lutein, phenolics, flavonoids and chlorophyll [1]. Drying consists of a complex process in which simultaneous heat and mass transfer occur. Several alterations occur during the drying of foods at many levels (physical, chemical, nutritional or sensorial) which are influenced by a number of factors, including processing conditions [2]. Temperature is particularly important because of the effects it produces at the chemical and also at the physical level, particularly colour and texture [3]. In the present work were evaluated the changes in sliced kiwi when exposed to air drying at different temperatures (50, 60, 70, 80 ºC), namely in terms of some chemical properties like ascorbic acid or phenolic compounds, physical characteristics like colour and texture and also at the sensorial level. All experiments followed standard established procedures and several replicates were done to assess each property. The results obtained indicated that moisture was reduced with drying by 74 to 87%, depending on the temperature. Also ascorbic acid decreased with drying, being 7% for 50 ºC and increasing up to 28% for the highest temperature (80 ºC). The phenolic compounds and antioxidant activity were also very much affected by the drying temperature. The water activity of the dried samples varied from 0.658 to 0.753, being compatible with a good preservation. Regarding colour, the total colour difference between the dried samples and the fresh sample was found to vary in the range 9.45 – 17.17. The textural parameters were also much affected by drying, namely hardness which decreased by 45 to 72 %, and all other parameters increased: cohesiveness (approximately doubled), springiness (increased 2 to 3 times) and chewiness which increased up to 2.5 times that off the fresh sample. Adhesiveness, which was observed for the fresh samples (-4.02 N.s) disappeared in all the dried samples. The sensorial analysis made to the dried samples allowed establishing the sensorial profiles as shown in Figure 1.

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Temporary ponds are seasonal wetland habitats subjected to extreme and unstable ecological conditions. Some are classified as priority habitats for conservation by the European Union Habitats Directive. Our study area was the coastal plain of southwest Portugal, which spans across 100km north to south and hosts a large number of temporary ponds as a consequence of climatic and edaphic characteristics. Field sampling of floristic and edaphic data was carried out in 24 temporary ponds every spring between 2005 and 2008. We recorded a total of 174 plant species identified within visually homogeneous plots. We included the data in a geographic information system and classified ponds according to their floristic composition, using a biotic regionalization analysis based on species presence/absence, which is a practical and unambiguous criterion. We found three significantly different groups of ponds which corresponded to an eco-physiognomic pond typology: Mediterranean temporary ponds, marshlands, and disturbed ponds. For the first two pond types we defined characteristic or indicator plant species. We searched also for relationships between pond type and a series of large-scale climatic, geographic, and geological variables, as well as local-scale physical and chemical properties of the soil. Pond type was distinguished by a complex combination of some of these variables, including environmental energy, soil texture, nitrogen content of the soil and pH. A practical way of discriminating between different

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In this Ph.D. project, original and innovative approaches for the quali-quantitative analysis of abuse substances, as well as therapeutic agents with abuse potential and related compounds were designed, developed and validated for application to different fields such as forensics, clinical and pharmaceutical. All the parameters involved in the developed analytical workflows were properly and accurately optimised, from sample collection to sample pretreatment up to the instrumental analysis. Advanced dried blood microsampling technologies have been developed, able of bringing several advantages to the method as a whole, such as significant reduction of solvent use, feasible storage and transportation conditions and enhancement of analyte stability. At the same time, the use of capillary blood allows to increase subject compliance and overall method applicability by exploiting such innovative technologies. Both biological and non-biological samples involved in this project were subjected to optimised pretreatment techniques developed ad-hoc for each target analyte, making also use of advanced microextraction techniques. Finally, original and advanced instrumental analytical methods have been developed based on high and ultra-high performance liquid chromatography (HPLC,UHPLC) coupled to different detection means (mainly mass spectrometry, but also electrochemical, and spectrophotometric detection for screening purpose), and on attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) for solid-state analysis. Each method has been designed to obtain highly selective, sensitive yet sustainable systems and has been validated according to international guidelines. All the methods developed herein proved to be suitable for the analysis of the compounds under investigation and may be useful tools in medicinal chemistry, pharmaceutical analysis, within clinical studies and forensic investigations.