Large-scale instabilities in a STOVL upwash fountain

The fountain flow created by two underexpanded axisymmetric, turbulent jets impinging on a ground plane was studied through the use of laser-based experimental techniques. Velocity and turbulence data were acquired in the jet and fountain flow regions using laser doppler velocimetry and particle image velocimetry. Profiles of mean and rms velocities along the jet centreline are presented for nozzle pressure ratios of two, three and four. The unsteady nature of the fountain flow was examined and the presence of large-scale coherent structures identified. A spectral analysis of the fountain flow data was performed using the Welch method. The results have relevance to ongoing studies of the fountain flow using large eddy simulation techniques

Anthocyanins in blue berries of Vaccinium padifolium

Twenty anthocyanins were isolated from the extract of the edible blue berries of Vaccinium padifolium (Uveira) by a combination of chromatographic techniques. Mainly on the basis of nuclear magnetic resonance techniques (1H, COSY, TOCSY, HSQC, HMBC, SEFT) they were identified as the 3-O-beta-glucopyranosides, 3-O-beta-galactopyranosides, 3-O-beta-arabinopyranosides and 3-O-sambubiosides (2'-O-beta-xylopyranosyl-O-beta-glucopyranosides) of delphinidin, cyanidin, petunidin,malvidin and peonidin. Anthocyanidin disaccharides have not been identified in the genus Vaccinium previously, and the 3-sambubiosides of peonidin, petunidin and malvidin are novel compounds.Fundação para a Ciência e Tecnologi

Synthesis of sub-5 nm Co-doped SnO2_2 nanoparticles and their structural, microstructural, optical and photocatalytic properties

A swift chemical route to synthesize Co-doped SnO$_2$ nanopowders is described. Pure and highly stable Sn$_{1-x}$Co$_x$O$_{2-\delta}$ (0 $\le$ x $\le$ 0.15) crystalline nanoparticles were synthesized, with mean grain sizes < 5 nm and the dopant element homogeneously distributed in substitutional sites of the SnO$_2$ matrix. The UV-visible diffuse reflectance spectra of the Sn$_{1-x}$Co$_x$O$_{2-\delta}$ samples reveal red shifts, the optical bandgap energies decreasing with increasing Co concentration. The Urbach energies of the samples were calculated and correlated with their bandgap energies. The photocatalytic activity of the Sn$_{1-x}$Co$_x$O$_{2-\delta}$ samples was investigated for the 4-hydroxylbenzoic acid (4-HBA) degradation process. A complete photodegradation of a 10 ppm 4-HBA solution was achieved using 0.02% (w/w) of Sn$_{0.95}$Co$_{0.05}$O$_{2-\delta}$ nanoparticles in 60 min of irradiation.Comment: 29 pages, 2 tables, 10 figure

Business model of non-governamental organizations for the development of the education sector in Mozambique: A construtivist approach

This research aims to determine the business model of non-governmental development organizations (NGDOs) of the education sector in Mozambique. The work adopts a constructivist methodological approach in two stages: (i) inductive, centered on the construction of a proposal of social business model Canvas from the observation of 15 NGDOs operating in the education sector in the country, based on a theoretical framework solidly supported in the literature; (ii) deductive, testing the proposed model using a panel technique that allowed the refinement and reconstruction of the proposal initially formulated. The paper contributes to the literature on social business models by making a pioneering validation of knowledge built in this area and in a field of application not yet explored. The contribution to international relations lies at the level of the data collected and information produced on international cooperation in Mozambique.info:eu-repo/semantics/publishedVersio

Colour and stability of pure anthocyanins influenced by pH including the alkaline region

This study on anthocyanin colour variation (intensity, lambda max, absorptivity) over the pH range 1-9 during 60 days of storage, was conducted on petunidin 3-[6-O-(4-O-E-p- coumaroyl-O-alfa-L-rhamnopyranosyl)-beta-D-glucopyranoside]-5-O-beta-D-glucopyranoside (petanin) and cyanidin 3-O-beta-D-glucopyranoside (cy3glc) at 10 and 23ºC. Compared to cy3glc, petanin afforded higher colour intensity and higher or similar stability throughout the whole pH range. At pH 4.0, 84% of petanin was intact after 60 days storage at 10ºC, while the corresponding solution of cy3glc was totally degraded. At pH 8.1 the colour intensity of petanin was even higher than at the lowest pH values. The visible lambda max absorption of petanin after 5 days at pH 8.1 at 10ºC was similar or higher than the corresponding absorptions of the fresh solutions of cy3glc at any pH. The use of anthocyanins like petanin as food colorants in slightly alkaline products (bakery, milk, egg, etc.) should therefore be considered at least in products with limited storage time kept in a refrigerator.Fundação para a Ciência e Tecnologi

Anthocyanin trisaccharides in blue berries of Vaccinium padifolium

Delphinidin 3-O-alfa-rhamnoside, malvidin 3-O-(6''-O-alfa-rhamnopyranosyl-beta-glucopyranoside) and the 3-O-(6''-O-alfa-rhamnopyranosyl-2''-O-beta-xylopyranosyl-beta-glucopyranosides) of cyanidin, petunidin and peonidin were isolated by various chromatographic techniques from the edible berries of Vaccinium padifolium. Their complete structures were elucidated mainly by one- and two-dimensional nuclear magnetic resonance spectroscopy. Together they account for 7% of the anthocyanin content in this species. No anthocyanidin 3-triglycoside, 3-rutinoside or 3-rhamnoside had previously been found in the genus Vaccinium. The 3-O-(6''-O-alfa- rhamnopyranosyl-2''-O-beta-xylopyranosyl-beta-glucopyranosides) of petunidin and peonidin are novel compounds.Fundação para a Ciência e Tecnologi

Modelling competing risks in nephrology research: an example in peritoneal dialysis

BACKGROUND: Modelling competing risks is an essential issue in Nephrology Research. In peritoneal dialysis studies, sometimes inappropriate methods (i.e. Kaplan-Meier method) have been used to estimate probabilities for an event of interest in the presence of competing risks. In this situation a competing risk analysis should be preferable. The objectives of this study are to describe the bias resulting from the application of standard survival analysis to estimate peritonitis-free patient survival and to provide alternative statistical approaches taking competing risks into account. METHODS: The sample comprises patients included in a university hospital peritoneal dialysis program between October 1985 and June 2011 (n = 449). Cumulative incidence function and competing risk regression models based on cause-specific and subdistribution hazards were discussed. RESULTS: The probability of occurrence of the first peritonitis is wrongly overestimated using Kaplan-Meier method. The cause-specific hazard model showed that factors associated with shorter time to first peritonitis were age (>=55 years) and previous treatment (haemodialysis). Taking competing risks into account in the subdistribution hazard model, age remained significant while gender (female) but not previous treatment was identified as a factor associated with a higher probability of first peritonitis event. CONCLUSIONS: In the presence of competing risks outcomes, Kaplan-Meier estimates are biased as they overestimated the probability of the occurrence of an event of interest. Methods which take competing risks into account provide unbiased estimates of cumulative incidence for each specific outcome experienced by patients. Multivariable regression models such as those based on cause-specific hazard and on subdistribution hazard should be used in this competing risk setting

Polyacylated anthocyanins from Hebe

Four acylated anthocyanins were isolated from flowers of Hebe spp. On the basis of LC-MS (Liquid Chromatography - Mass Spectrometry) and NMR (Nuclear Magnetic Resonance) techniques, they were identified as (1) cyanidin 3-O-[2-O-(6-O-(E-caffeoyl)-beta-glucopyranosyl)-6-O-(E-p-coumaroyl)-beta-glucopyranoside]-5-O-beta-glucopyranoside, (2) cyanidin 3-O-[2-O-(6-O-(E-p-coumaroyl)-beta-glucopyranosyl)-6-O-(E-p-coumaroyl)-beta-glucopyranoside]-5-O-beta-glucopyranoside, (3) cyanidin 3-O-[2-O-(6-O-(E-caffeoyl)-beta-glucopyranosyl)-6-O-(E-p-coumaroyl)-beta-glucopyranoside]-5-O-[6-O-(malonyl)-beta-glucopyranoside], and (4) cyanidin 3-O-[2-O-(6-O-(E-p-coumaroyl)-beta-glucopyranosyl)-6-O-(E-p-coumaroyl)-beta-glucopyranoside]-5-O-[6-O-(malonyl)-beta-glucopyranoside]. Pigments 2 and 4 are novel compounds.Fundação para a Ciência e Tecnologi

Effect of hydroxyethyl starch on acute renal injury in a model of hepatic ischemia-reperfusion

BACKGROUND: Hepatic vascular control techniques employed during liver surgery are usually associated with ischemia-reperfusion injury, which could cause acute renal dysfunction. The murine model has been used in the study of this injury. Hydroxyethyl starch has recognized anti-inflammatory properties and improves microcirculation. Third generation hydroxyethyl starches, namely 130/0.4, show a better safety profile than previous molecules. OBJECTIVES: Evaluation of renal injury in a murine model of partial normothermic hepatic ischemia-reperfusion injury and assessment of hydroxyethyl starch 130/0.4 effect on this injury. METHODS: Seventy-two male Wistar rats were randomized into six groups with identical characteristics (n = 12 x 6). In three of them, the ischemia-reperfusion injury groups, we placed a clamp in the vascular pedicle of the median and left liver lobes, inducing hepatic ischemia (70%), and removed the clamp 60 minutes later (IRI + HES and IRI + HS groups, with HES or hypertonic saline (7.5%) administration during reperfusion, respectively, and IRI group, without fluid therapy). The control groups were sham-operated without hepatic ischemia and treated likewise (sham + HES, sham + HS and sham groups). After 120 minutes of reperfusion in the ischemia-reperfusion injury groups and 180 minutes in the controls we drew blood from the aorta artery for creatinine, urea and alanine aminotransferase quantification and removed kidney and liver samples for histopathological analysis. RESULTS: As already published by our group, the partial hepatic ischemia-reperfusion injury model showed liver injury. In the present work, the IRI group had higher creatinine, urea and histopathological score than sham (p < 0.05). Creatinine and urea mean concentrations were significantly lower both in IRI+HES (23.08 µmol/L and 8.38 mmol/L, respectively) and IRI + HS (26.59 µmol/L and 7.82 mmol/L) when compared to IRI (40.101 µmol/L and 11.25 mmol/L). There was no significant difference between IRI + HES and IRI + HS groups (serum markers and histopathology).Conclusion: The hepatic ischemia-reperfusion injury murine model was effective in producing kidney injury. Both the hydroxyethyl starch 130/0.4 and the hypertonic saline protected the kidney in this context and were not harmful for this organ in the controls. Further studies are necessary to assess clinical implications of hydroxyethyl starch 130/0.4 administration in liver surgery