Search

The present work shows the application of nickel- and magnesium-crosslinked gellan microspheres in ionic and affinity capture strategies to directly extract hSCOMT from the complex Komagataella pastoris lysate through a simple batch method. Both formulations present similar morphology, but nickel–crosslinked microspheres present higher crosslinker content and smaller diameters. Four different capture strategies were established, by manipulating the ionic strength, pH, temperature and competing agents' presence. The most promising results for hSCOMT capture and clarification were obtained employing an ionic strategy with nickel-crosslinked microspheres and an affinity strategy with magnesium-crosslinked microspheres at 4 °C. The bioactivity results (200%) and purification degree (70%) of hSCOMT captured by the ionic strategy were more satisfactory probably due to the soft ionic conditions used (100 mM NaCl). For the first time, the gellan polysaccharide versatility was demonstrated in the microsphere application for the direct capture of hSCOMT from a complex lysate, simplifying isolation biotechnological procedures. Unlabelled Image • Formulation and characterization of gellan microspheres reinforced with nickel and magnesium crosslinkers • Human SCOMT capture at 4 °C employing an ionic strategy with nickel-crosslinked microspheres • Human SCOMT capture at 4 °C employing an affinity strategy with magnesium-crosslinked microspheres • The ionic strategy with nickel-crosslinked microspheres, allows a bioactivity recovery under 200%. [ABSTRACT FROM AUTHOR]

• A framework to evaluate and compare uncertainty forecasts of power system state. • Comparing alternative uncertainty models for branch load security assessment. • Assessing the benefits of using probabilistic over deterministic forecasts. • The quality and scalability of the framework is applied on the French EHV/HV system. • The added values of uncertainty forecasts are illustrated for a N-2 contingency. This paper presents a generic framework to evaluate and compare the quality of the uncertainties provided by probabilistic forecasts of power system state when used to perform security assessment for branch overloads. Besides exploiting advanced univariate and multivariate metrics that are traditionally used in weather prediction, the evaluation is complemented by assessing the benefits from exploiting probabilistic forecasts over the current practices of using deterministic forecasts of the system operating conditions. Another important feature of this framework is the provision of parameters tuning when applying flow probabilistic forecasts to perform security assessment for branch overloads. The quality and scalability of this framework is demonstrated and validated on recent historical data of the French transmission system. Although being developed to address branch overload problems, with proper adaptations, this work can be extended to other power system security problems. [ABSTRACT FROM AUTHOR]

This work discusses the optimization of different synthesis parameters for a low emitting urea-formaldehyde (UF) resin. Industrially, this resin was synthesized using the alkaline-acid process (alkaline methylolation and acidic condensation) at different values of pH, temperature (T) and final viscosity and characterized according to different analytical methods. Particleboards (PBs) were produced using different pressing times and characterized according to the standard tests. A statistical analysis (ANOVA) was performed, and the main conclusion is that small changes on the synthesis of resins parameters do not affect the performance of PBs. [ABSTRACT FROM AUTHOR]

In this work, the thermal stability of TiAg x thin films, deposited by magnetron sputtering, was evaluated, envisaging their application in biomedical devices, namely as electrodes for biosignal acquisition. Based on the composition and microstructural characterization, a set of four representative TiAg x thin films was selected in order to infer whether they are thermally stable in terms of functional properties. In order to achieve this purpose, the structural and morphological evolution of the films with annealing temperature was correlated with their electrical, mechanical and thermal properties. Two distinct zones were identified and two samples from each zone were extensively analysed. In the first zone (zone I), Ti was the main component (Ti-rich zone) while in the second, zone II, the Ag content was more significant. The selected samples were annealed in vacuum at four different temperatures up to 500 °C. For the samples produced within zone I, small microstructural changes were observed due to the recrystallization of the Ti structure and grain size increment. Also, no significant changes were observed with annealing temperature regarding the films' functional properties, being thermally stable up to 500 °C. For higher Ag contents (zone II) the energy supplied by thermal treatments was sufficient to activate the crystallization of Ti–Ag intermetallic phases. A strong increase of the grain size of these phases was also reported. The structural and morphological organization proved to be determinant for the physical responses of the TiAg x system. The hardness and Young's modulus were significantly improved with the formation of the intermetallic phases. The silver addition and annealing treatments also played an important role in the electrical conductivity of the films, which was once again improved by the formation of Ti–Ag phases. The thermal diffusivity of the films was practically unchanged with the heat-treatment. This set of results shows that this intermetallic-like thin film system has good thermal stability up to high temperatures (as high as 500 °C), which in case of the highest Ag content zone is particularly evident for electrical and mechanical properties, showing an important improvement. Hardness increases about three times, while resistivity values become half of those from the lowest Ag content zone. These sets of characteristics are consistent with the targeted applications, namely in terms of biomedical sensing devices. [ABSTRACT FROM AUTHOR]

Evidence has linked excessive salt consumption to the development of chronic degenerative diseases. Therefore, special attention has been given to the consumption of healthier products with reduced sodium contents. This study aimed to develop a Mozzarella cheese with a reduced sodium content using a mixture of salts through acceptance testing and temporal sensory evaluation. The following 3 formulations of Mozzarella cheese were prepared: formulation A (control), which was produced only with NaCl (0% sodium reduction), formulation B (30% sodium reduction), and formulation C (54% sodium reduction). Every formulation was produced using a mixture of salts consisting of NaCl, KCl, and monosodium glutamate at different concentrations. The products underwent sensory acceptance tests, and the time intensity and temporal dominance of sensations were evaluated. The proportions of salts used did not cause strange or bad tastes but did result in lower intensities of saltiness. Mozzarella with low sodium content (B and C) had a sensory acceptance similar to that of traditional Mozzarella (A). Therefore, the use of a mixture of salts consisting of NaCl, KCl, and monosodium glutamate is a viable alternative for the production of Mozzarella, with up to a 54% reduction in the sodium content while still maintaining acceptable sensory quality. [ABSTRACT FROM AUTHOR]

Abstract: The current study presents, for the first time, a long-term organic speciation of aerosol at the Cape Verde archipelago. The Cape Verde location, in the Atlantic Ocean, provides a unique laboratory to study background aerosol, long-range transport, aerosol mixing with mineral dust, biomass burning and sea surface components. In order to contribute to a better understanding of this environment, a one-year long measurement campaign was performed in Praia City, Santiago Island. PM10 concentrations (20.5–370 μg/m3) and the organic composition of PM10 were influenced by the African dust influxes. The carbonaceous content of PM10 was very low, suggesting that most of the mass has mineral origin. The PM10 composition was essentially characterised by a large variety of organic compounds, which can be grouped into general compound classes, such as n-alkanes, n-alkanols, n-acids and sugars. The n-alkane total concentrations varied from 3.77 to 53.2 ng/m3. The n-alkanols distribution showed a significant biogenic contribution whether from microbial origin or from epicuticular plants during African dust outbreaks. The total concentrations of n-alkanoic acids varied from 0.011 to 4.51 ng/m3. The lower n-alkenoic acids content, obtained during the periods of long-range transport from Africa, indicated a more aged aerosol. The monosaccharide anhydrides were detected in all samples with a range of concentrations from 2.06 to 12.7 ng/m3. [Copyright &y& Elsevier]

Abstract: Lorazepam is a recalcitrant drug, frequently quantified in WWTPs’ effluents and surface waters, even though it has never been studied under accelerated phototransformation processes. Therefore, the main goal of the present work was to comparatively evaluate lorazepam’s photolytic and photocatalytic degradation kinetics using two experimental systems: a lab-scale photochemical reactor provided with an UV medium pressure mercury lamp (LsAUVP) and a solar pilot plant with compound parabolic collectors (SPP-CPCs). Lorazepam was tested in its most commercialized dosage form in Portugal – Lorenin® pills, 1mg (Wyeth), thus simulating a more realistic scenario. Preliminary results showed that, using the LsAUVP apparatus, lorazepam’s highest degradation yield was obtained through photolysis, while using the SPP-CPCs system, the best degradation performance was achieved by photocatalysis with a TiO2 concentration of 200mgL−1. Furthermore, the degradation kinetic constant obtained for the optimized method when using the SPP-CPCs system (k =1.49±0.03LkJ−1) was higher than that with the LsAUVP set-up (k =0.131±0.006LkJ−1), which in terms of necessary accumulated UV energy for complete lorazepam degradation, considering the respective method’s detection limit (MDL), corresponds to ca. 3 and 25kJL−1, respectively. [Copyright &y& Elsevier]

Abstract: Emerging pollutants, such as pharmaceuticals, are widely disseminated in the aquatic media. Though in low concentrations in the environment, they still pose concerns mainly over potential chronic toxicity effects. Consequently, this work reports on the successful attempt to develop a photocatalytic treatment method, using suspended TiO2 in a concentration of 200mgL−1 and solar UV radiation as the photon source, firstly designed for lorazepam (Lorenin® pills) degradation and further applied to the treatment of a real municipal WWTP effluent, containing several other emerging contaminants (ECs). Initial effluent physicochemical characterization revealed the presence of 22 pharmaceutical compounds in moderate concentrations (maximum of 680ngL−1, except for diclofenac ∼24μgL−1 and hydrochlorothiazide ∼3μgL−1) and a low dissolved organic carbon (DOC) content. Therefore, the main purpose of the work was not to increase the effluent’s biodegradability, but to improve the removal rates of the several present ECs. Pharmaceuticals’ degradation kinetics, using a solar pilot plant with CPCs, were thoroughly studied. A pseudo-first order kinetic model was able to successfully predict the experimental data. The overall treatment was considered efficient, with a complete removal of the majority of these micropollutants, except for ciprofloxacin (35%), ketoprofen (61%) and bisoprolol (77%). Nevertheless, a small increase in the reaction time could easily accomplish their total degradation. Zahn–Wellens biodegradability assay allowed withdrawing some conclusions about which pharmaceuticals could be degraded by means of biotreatment, thus avoiding the need to apply a photocatalytic treatment. Finally, Vibrio fischeri acute toxicity test showed that the effluent itself presented no significant toxicity and that the intermediate oxidation compounds, possibly formed during phototreatment, did not reflect any significant increase of toxicity. [Copyright &y& Elsevier]

Polycyclic aromatic hydrocarbon (PAH) extracts of fine particles (PM2.5) collected from combustion of seven wood species and briquettes were tested for mutagenic activities using Ames test with Salmonella typhimurium TA98 and TA100. The woods were Pinus pinaster (maritime pine), Eucalyptus globulus (eucalypt), Quercus suber (cork oak), Acacia longifolia (golden wattle), Quercus faginea (Portuguese oak), Olea europea (olive), and Quercus ilex rotundifolia (Holm oak). Burning experiments were done using woodstove and fireplace, hot start and cold start conditions. A mutagenic response was recorded for all species except golden wattle, maritime pine, and briquettes. The mutagenic extracts were not correlated with high emission factors of carcinogenic PAHs. These extracts were obtained both from two burning appliances and start-up conditions. However, fireplace seemed to favour the occurrence of mutagenic emissions. The negative result recorded for golden wattle was interesting, in an ecological point of view, since after confirmation, this invasive species, can be recommended for domestic use. [Copyright &y& Elsevier]

Abstract: Gaseous and particulate samples from the smoke from prescribed burnings of a shrub-dominated forest with some pine trees in Lousã Mountain, Portugal, in May 2008, have been collected. From the gas phase Fourier transform infrared (FTIR) measurements, an average modified combustion efficiency of 0.99 was obtained, suggesting a very strong predominance of flaming combustion. Gaseous compounds whose emissions are promoted in fresh plumes and during the flaming burning phase, such as CO2, acetylene and propene, produced emission factors higher than those proposed for savannah and tropical forest fires. Emission factors of species that are favoured by the smouldering phase (e.g. CO and CH4) were below the values reported in the literature for biomass burning in other ecosystems. The chemical composition of fine (PM2.5) and coarse (PM2.5–10) particles was achieved using ion chromatography (water-soluble ions), instrumental neutron activation analysis (trace elements) and a thermal–optical transmission technique (organic carbon and elemental carbon). Approximately 50% of the particulate mass was carbonaceous in nature with a clear dominance of organic carbon. The organic carbon-to-elemental carbon ratios up to 300, or even higher, measured in the present study largely exceeded those reported for fires in savannah and tropical forests. More than 30 trace elements and ions have been determined in smoke aerosols, representing in total an average contribution of about 7% to the PM10 mass. [Copyright &y& Elsevier]

Abstract: Fine (PM2.5) and coarse (PM2.5–10) smoke particles from controlled biomass burnings of a shrub-dominated forest in Lousã Mountain, Portugal, enabled the quantification by chromatographic techniques of several molecular tracers for the combustion of Mediterranean forest ecosystems, which could be conducive to source apportionment studies. The major organic components in the smoke samples were pyrolysates of vegetation cuticles, mainly comprising steradienes and sterol derivatives, carbohydrates from the breakdown of cellulose, aliphatic lipids from vegetation waxes and methoxyphenols from the lignin thermal degradation. Most of these compounds are chiefly found in fine particles. Polycyclic aromatic hydrocarbons (PAH) were also present as minor constituents. Anhydrosugar and PAH molecular diagnostic ratios were applied as source assignment tools. Some biomarkers are reported for the first time in biomass burning smoke. [Copyright &y& Elsevier]

Abstract: The photochemical persistence of quinalphos, one of the most widely used organophosphorous insecticides, was investigated in a variety of environmental matrices such as natural waters and soils of different composition. Simulated solar irradiation was obtained using a xenon arc lamp (Suntest CPS+ apparatus) giving an irradiation intensity of 750Wm−2 equivalent to a light dose per hour of irradiation of 2700kJm−2. The phototransformation rates were determined using solid-phase microextraction (SPME) and ultrasonic extraction (USE) coupled to GC-FTD, while the identification of photoproducts was carried out by GC–MS. In water samples, the degradation kinetics followed a pseudo-first-order reaction and photolysis half-lives ranged between 11.6 and 19.0h depending on the constitution of the irradiated media. Dissolved organic matter (DOM) has a predominant retarding effect, while nitrate ions accelerated the photodegradation kinetics. In soil samples, the degradation kinetics was monitored on 1mm soil layer prepared on glass TLC plates. The kinetic behaviour of quinalphos was complex and characterized by a double step photoreaction, fast in the first 4h of irradiation followed by a slow degradation rate up to 64h. The photolysis half-life of quinalphos was shorter in sandy soil compared to the rest of the soil samples, varying between 16.9 and 47.5h, and showing a strong dependence on the composition of the irradiated media. Among the transformation products formed mainly through photohydrolysis and photoisomerization processes, some photoproduct structures were proposed according to their mass spectral information. [Copyright &y& Elsevier]

Abstract: A low cost pH electrode was prepared and characterized. A thin film of RuO2–TiO2 (70–30) mol% was prepared using the Pechini method and deposited on a Ti substrate. The slope of the potential versus pH curve is 56.03mVpH−1 and the electrode is insensible to the presence of Li+, Na+ and Ca+ in the solution. [Copyright &y& Elsevier]

Abstract: In order to reduce the amount of sample to be collected and the time consumed in the analytical process, a broad range of analytes should be preferably considered in the same analytical procedure. A suitable methodology for pesticide residue analysis in soil samples was developed based on ultrasonic extraction (USE) and gas chromatography–mass spectrometry (GC–MS). For this study, different classes of pesticides were selected, both recent and old persistent molecules: parent compounds and degradation products, namely organochlorine, organophosphorous and pyrethroid insecticides, triazine and acetanilide herbicides and other miscellaneous pesticides. Pesticide residues could be detected in the low- to sub-ppb range (0.05–7.0μgkg−1) with good precision (7.5–20.5%, average 13.7% R.S.D.) and extraction efficiency (69–118%, average 88%) for the great majority of analytes. This methodology has been applied in a monitoring program of soil samples from an intensive horticulture area in Póvoa de Varzim, North of Portugal. The pesticides detected in four sampling programs (2001/2002) were the following: lindane, dieldrin, endosulfan, endosulfan sulfate, 4,4′-DDE, 4,4′-DDD, atrazine, desethylatrazine, alachlor, dimethoate, chlorpyrifos, pendimethalin, procymidone and chlorfenvinphos. Pesticide contamination was investigated at three depths and in different soil and crop types to assess the influence of soil characteristics and trends over time. [Copyright &y& Elsevier]

Nanocrystalline hydrogenated silicon films were grown by radiofrequency magnetron sputtering in an mixed Argon/Hydrogen (30%/70%) plasma. For some series Helium or Nitrogen was added to the gas mixture. The films were grown at 250 °C for total different pressures varying from 5 to 15 Pa. The crystalline fraction increases with pressure from 85 to 93% but at the same time the porosity of the films increases from 11 to 19%. This relatively high porosity leads to an important post-growth contamination of oxygen as revealed by IR absorption spectroscopy and nuclear reaction analysis (NRA) and can explain the low stress observed in these films. The Electron spin resonance performed at 35 GHz indicates the presence of oxygen in the surroundings of the paramagnetic defects. The spin density is of the order of some 1017 cm−3, independent of the growth pressure and in agreement with photothermal deflection spectroscopy results. From the IR spectroscopy and NRA one can deduce that most of the oxygen in the films is bound to silicon. Helium dilution of the plasma at 5 Pa tends to reduce the porosity and the oxygen contamination in the film but above 30% He dilution, the crystalline fraction decreases. When nitrogen is introduced into the plasma during growth the films become amorphous, even for very small partial pressures of N2. [Copyright &y& Elsevier]