1,053 research outputs found
Distribución espacial de los anélidos poliquetos de fondos blandos en la ensenada de baiona (RÃa de Vigo, Galicia, Noroeste de España)
The spatial distribution of the polychaete fauna in the subtidal soft-bottoms of the Ensenada de Baiona (Galicia, NW Spain) was studied by means of quantitative sampling and multivariate analyses. Several faunistic assemblages were determined, which were closely related to the sediment distribution pattern in the inlet. The coarse-medium sand fauna was mainly dominated by syllids and pisionids. Finer sediments (fine sand to mud) showed a greater abundance of deposit-feeding species, mostly spionids, cirratulids and capitellids. The greatest number of species and diversity were found in mixed sediments with medium and fine sand. Organically enriched muds around Baiona harbour have an impoverished fauna, with a high dominance of Cossura pygodactylata Jones, 1956.La distribución espacial de la fauna de poliquetos de fondos blandos submareales de la ensenada de Baiona (Galicia, NW España) ha sido estudiada mediante técnicas de muestreo cuantitativo. Los análisis multivariantes diferenciaron varias asociaciones faunísticas, que coinciden en gran medida con los patrones de distribución sedimentaria en el área estudiada. La fauna de arenas gruesas y medias está dominada principalmente por sílidos y pisiónidos, mientras que los sedimentos más finos (arenas finas a fangos) muestran una mayor abundancia de organismos depositívoros como espiónidos, cirratúlidos y capitélidos. Se han observado los mayores valores de riqueza específica y diversidad en sedimentos mixtos de arena fina y media. Los fangos orgánicamente enriquecidos del puerto de Baiona muestran una fauna empobrecida con una gran dominancia de Cossura pygodactylata.  
Patrones de distribución de la familia Syllidae (Annelida: Polychaeta) en praderas de las fanerógamas marinas Zostera marina y Zostera noltei en la ensenada de O Grove (Galicia, NO España)
This paper describes the distribution and composition of the syllid fauna inhabiting seagrass meadows in the Ensenada de O Grove (NW Spain). Samples were collected on muddy sediments colonized by either Zostera marina L., Zostera noltei Hornemann or by a mixed meadow with both species. Syllids were dominant (13340 individuals; 37% of total polychaete abundance), including 22 species (12 genera). The mixed meadows housed the highest number of species and the Z. noltei meadow had practically no syllids. The dominant species were Exogone naidina, Parapionosyllis elegans, Parexogone hebes and Prosphaerosyllis campoyi ( > 80% of total abundance). Carnivores (mainly species of Parapionosyllis, Amblyosyllis, and Streptosyllis) were dominant, especially in muddy sand with either Z. marina or Z. noltei and sandy mud with a mixed meadow. The most important abiotic variables for explaining the composition and distribution of the syllid fauna were bottom water salinity, sorting coefficient and carbonate content. The highest number of species was recorded at sites with a high salinity and carbonate content and the lowest at sites with a high sorting coefficient.El presente trabajo describe la distribución y composición de los sÃlidos encontrados en las praderas de fanerógamas de la Ensenada de O Grove (NO España). Los fondos fangosos estudiados están colonizados por Zostera marina L., Zostera noltei Hornemann o por ambas especies de fanerógamas. Los sÃlidos fueron la familia de poliquetos dominante numéricamente (13340 individuos, 37% total de la abundancia total de poliquetos) representados por 22 especies (12 géneros). Los fangos arenosos con pradera mixta albergaron el mayor número de especies de sÃlidos mientras que en los fondos de fango con Z. noltei estuvieron prácticamente ausentes. Las especies más abundantes fueron Exogone naidina, Parapionosyllis elegans, Parexogone hebes y Prosphaerosyllis campoyi ( > 80% abundancia total). Los carnÃvoros (principalmente especies de Parapionosyllis, Amblyosyllis y Streptosyllis) fueron dominantes especialmente en arenas fangosas con Z. marina o Z. noltei y en fangos arenosos con una pradera mixta. Las variables abióticas más importantes a la hora de explicar la composición y distribución de los sÃlidos fueron la salinidad del agua de fondo, el coeficiente de selección y el contenido en carbonatos; asÃ, se ha encontrado un elevado número de especies en estaciones con salinidad y contenido en carbonatos más elevados, en comparación con estaciones con un mayor coeficiente de selección
Modelling autocatalytic behaviour of a food model system- sucrose thermal degradation at high concentrations
Sucrose thermal degradation is an important reaction in the food industry. When in concentrated and neutral solutions, pure sucrose presents a lag phase in the reaction. This work aimed at: (i) modelling sucrose thermal degradation autocatalytic behaviour and (ii) studying the concentration and temperature effects on kinetic parameters. Isothermal experiments were conducted at temperatures ranging
from 100 to 180 C, using solutions with varying water content (3.58–30.03 (% w/w)). The logistic and Gompertz sigmoidal equations
were modified and reparameterised, in order to describe degradation behaviour with kinetic parameters with physical meaning (maximum reaction rate, kmax, and lag time, k). In both models these parameters presented an Arrhenius type dependence on temperature. Following a mixed model effect methodology, the concentration dependence was observed on the Arrhenius parameters. This concentration effect was included in the proposed kinetic models, which were able to successfully describe experimental data
Omacetaxine may have a role in chronic myeloid leukaemia eradication through downregulation of Mcl-1 and induction of apoptosis in stem/progenitor cells
Chronic myeloid leukaemia (CML) is maintained by a rare population of tyrosine kinase inhibitor (TKI)-insensitive malignant stem cells. Our long-term aim is to find a BcrAbl-independent drug that can be combined with a TKI to improve overall disease response in chronic-phase CML. Omacetaxine mepesuccinate, a first in class cetaxine, has been evaluated by clinical trials in TKI-insensitive/resistant CML. Omacetaxine inhibits synthesis of anti-apoptotic proteins of the Bcl-2 family, including (myeloid cell leukaemia) Mcl-1, leading to cell death. Omacetaxine effectively induced apoptosis in primary CML stem cells (CD34<sup>+</sup>38<sup>lo</sup>) by downregulation of Mcl-1 protein. In contrast to our previous findings with TKIs, omacetaxine did not accumulate undivided cells <i>in vitro</i>. Furthermore, the functionality of surviving stem cells following omacetaxine exposure was significantly reduced in a dose-dependant manner, as determined by colony forming cell and the more stringent long-term culture initiating cell colony assays. This stem cell-directed activity was not limited to CML stem cells as both normal and non-CML CD34<sup>+</sup> cells were sensitive to inhibition. Thus, although omacetaxine is not leukaemia stem cell specific, its ability to induce apoptosis of leukaemic stem cells distinguishes it from TKIs and creates the potential for a curative strategy for persistent disease
Modelling colour changes during the caramelisation reaction
Sucrose solutions, with concentrations near or superior to saturation, present high potentialities for the candy and pastry industries. The development of colour in a neutral and highly concentrated sucrose solution (16.32%(w/w) water content) subjected to isothermal heat treatment (in the 100–160 C range) was investigated. Under such conditions, sucrose degrades through caramelisation and 5- hydroxymethylfurfural (HMF) is formed. Colour development was monitored through lightness/darkening (L/L0) and total colour difference (TCDH) changes during reaction course. Kinetic behaviour was mathematically described using modified Gompertz equations.
The effect of temperature on the reaction was described by an Arrhenius type dependency. Colour development and sucrose degradation kinetic parameters were compared and similar lag phases were found. However, the same was not observed for reactions rate, indicating that not only sucrose degradation contributes to colour development. To investigate the colour development/HMF content relationship,
a fractional conversion and a power law models where successfully proposed to express, respectively, L/L0 and TCDH dependence on HMF content
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International survey of Cronobacter sakazakii and other Cronobacter spp. in follow up formulas and infant food
A coordinated survey for Cronobacter and related organisms in powdered infant formula, follow up formula and infant foods was undertaken by 8 laboratories in 7 countries in recognition of and in response to the data needs identified in an FAO/WHO call for data in order to develop global risk management guidance for these products. The products (domestic and imported) were purchased from the local market and were categorised according to their principle ingredients. A total of 290 products were analysed using a standardised procedure of pre-enrichment in 225 ml Buffered Peptone Water (BPW), followed by enrichment in Enterobacteriaceae Enrichment (EE) broth, plating on the chromogenic Cronobacter Druggan–Forsythe–Iversen (DFI) agar and presumptive identification with ID 32 E. Presumptive Cronobacter isolates were identified using 16S rRNA gene sequence analysis. Aerobic plate counts (APC) of the products were also determined on nutrient agar. Fourteen samples had APC > 105 cfu/g, 3 of which contained probiotic cultures. C. sakazakii was isolated from 27 products; 3/91 (3%) follow up formulas (as defined by Codex Alimentarius Commission), and 24/199 (12%) infant foods and drinks. Hence C. sakazakii was less prevalent in follow up formula than other foods given to infants over the same age range. A range of other bacteria were also isolated from follow up formulas, including Acinetobacter baumannii, Enterobacter cloacae, Klebsiella pneumoniae, Citrobacter freundii, and Serratia ficaria. There was significant variation in the reconstitution instructions for follow up formulas. These included using water at temperatures which would enable bacterial growth. Additionally, the definition of follow up formula varied between countries
Cerebral Sinovenous Thrombosis in Children: Clinical Presentation and Extension, Localization and Recanalization of Thrombosis
Many important questions regarding pathophysiology and treatment of cerebral sinovenous thrombosis need clarification and may depend on further knowledge on the etiology, site, extension and recanalization of the thrombosis. We studied these variables in a cohort of children and adolescents from seven Portuguese Centers. We conclude from our results that the deep venous system and the superior longitudinal sinus are less frequently affected with thrombosis but have a greater potential for serious neurologic disease and for major sequelae. Non-recanalization, at least in the long term, is not an adverse prognostic
factor. Extensive propagation of the thrombus from the initial site of origin seems to be common. The early identification of risk factors and their treatment coupled with an aggressive attitude towards diagnosis and treatment for thrombosis involving the deep venous system would be warranted
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