595 research outputs found

    Proposal of a method for fluorimetric analysis of malvin in red wines

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    A fluorimetric method for the quantitative determination of malvin (malvidin 3,5-diglucoside) in red wines is described. The method is based on previous fractionation of the wine in a Polyclar AT column and later formation of a fluorophore, by oxidation of the malvin. The proposed method has good precision and accuracy and when applied to hybrid red wines affords results significantly comparable with those obtained by HPLC

    Influence of methane and carbon monoxide in the volumetric behaviour of the anthropogenic CO2: Experimental data and modelling in the critical region

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    Density measurements of the systems CO 2 + CH 4 at T = 304.21 K and CO 2 + CO at T = 304.21 and 308.15 K were carried out at pressures and compositions of interest in the process of transport and storage of CO 2 (CCS technology): P = 0.1 to 20 MPa, and xCO 2 ≥0.97. From the experimental P––T –xCO 2 data, we have studied the dependence of the isothermal compressibility, the excess molar volume, and the par- tial molar volume of the solute with composition, pressure and temperature within the critical region. We have modelled the volumetric behaviour of these systems with Peng–Robinson, PC-SAFT and GERG Equations of State, thus validating these equations under the conditions considered. Furthermore, we have confirmed the weakly attractive behaviour of these systems by performing a study of the interac- tions between solvent molecules, CO 2 , and those of the solute, CO or CH 4 , using the Krichevskii Function concept and the Kirkwood–Buff Theory. Finally, we have quantified the influence of small amounts of CH 4 and CO in the transport of anthropogenic CO 2 through several normalized parameters, related to the design and operation of the fluid transport process

    High-pressure speed of sound in pure CO2 and in CO2 with SO2 as an impurity using methanol as a doping agent

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    Reliable speed of sound, c, values in CO2- rich mixtures and pure CO2 are required for carbon capture and storage (CCS) technology but are difficult to determine, particularly at relatively high frequencies. We tested the suitability of methanol as doping agent to obtain accurate c values in CCS systems at 5 MHz. We measured c in seven CO2-rich, CO2 + methanol mixtures between 263.15 and 323.15 K and up to 196.30 MPa, and we extrapolated the values to obtain c in pure CO2. Additionally, we measured c from 263.15 to 373.19 K and up to 190.10 MPa in two CO2-rich, CO2 + SO2 mixtures with the same SO2 composition, which is of interest for CCS, with one mixture doped with methanol. We compared our results for pure CO2 with the literature and the Span and Wagner equation of state (EoS). We validated the PC-SAFT EoS and the modeling with the REFPROP 9 software for the mixtures by comparing the predicted values with our experimental data under the studied conditions. We conclude that methanol is a suitable doping agent to measure c in pure CO2 and CO2-rich mixtures. For the CO2 + SO2 mixtures, the effect of methanol on the experimental values is small and negligible for modeling

    Solvothermal synthesis and characterization of ytterbium/iron mixed oxide nanoparticles with potential functionalities for applications as multiplatform contrast agent in medical image techniques

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    A solvothermal route to prepare Glutathione capped hybrid ytterbium/iron oxide nanoparticles with potential applications as multiplatform contrast agent in medical image techniques has been developed. The influence of ytterbium/iron molar ratio used as precursor, as well as the degree of the autoclave filling on the structural and morphological characteristics of the obtained nanoparticles has been extensively studied. Although all nanoparticles present similar composition, with YbFeO3 being the majority phase, size and morphology of the as synthetized nanoparticles are highly influenced by the critical temperature and by the over -saturation reached during the solvothermal process. We have demonstrated that glutathione properly functionalizes the hybrid nanoparticles, increasing their colloidal stability and decreasing their cytotoxicity. Additionally, they show good imaging in magnetic resonance and X-ray computerized tomography, thereby indicating promising potential as a dual contrast agent. This work presents, for the first time, glutathione functionalized ytterbium/iron oxide nanoparticles with potential applications in Biomedicine.12 página

    Phylogenenetic approach of the section Bulbocodii D.C. of Narcissus based on cpDNA. A case of taxonomic inflation ?

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    In this paper, we analyzed the phylogeny of the section Bulbocodii (genus Narcissus; Amarillydaceae) using the matK and trnL-F fragments of cpDNA in order to review the validity of the recognized taxa. Our results indicate that Narcissus obesus should be considered a valid species, and that N. blancoi is a distinct taxon. In addition, seven previously recognized species, N. juressianus, N. subnivalis, N. graellsii, N. conspicuus, N. citrinus, N. nivalis, and N. quintanilhae, should be assigned to an infraspecific rank under N. bulbocodium, as they are not valid species. In addition, we analyzed the distribution of the three morphological characters widely used in the systematics of this section and found that their variation does not agree with the phylogenetic results, rendering these characters limited taxonomical utility. This result suggests that the section Bulbocodii shows high morphological lability, which can explain the proliferation of nominal speciesinfo:eu-repo/semantics/publishedVersio

    Trehalose-based siamese twin amphiphiles with tunable self-assembling, DNA nanocomplexing and gene delivery properties

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    An original family of multivalent vectors encompassing gemini and facial amphiphilicity, namely cationic Siamese twin surfactants, has been prepared fromthe disaccharide trehalose; molecular engineering lets us modulate the self-assembling properties and the topology of the nanocomplexes with plasmid DNA for efficient gene delivery in vitro and in vivo

    Anemia crónica en el trasplante cardiaco: prevalencia, factores predisponentes y significado pronóstico

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    [Abstract] Introduction and objectives. Data on chronic anemia following heart transplantation (HT) are scarce and contradictory. Our aims were to determine the prevalence of chronic anemia after HT, to identify predisposing factors for the condition at 12 months, and to evaluate its influence on mediumterm and long-term survival. Methods. Retrospective analysis of patients who underwent HT between 1991 and 2005 (n=457). Chronic anemia was defined as a hemoglobin level <12 g/dL. Results. The prevalence of post-HT chronic anemia was 75.5% at 1 month, 31% at 12 months, and 26.2% at 120 months. The condition was significantly more prevalent among women than men. Predisposing factors for chronic anemia 1 year post-HT were mild-to-moderate chronic renal failure (ie, creatinine level > 1.5 mg/dL; odds ratio [OR]=2.8; 95% confidence interval [CI], 1.5-5.0), female sex (OR=6.4; 95% CI, 3.1-13.2), and immunosuppression with mycophenolate mofetil compared with azathioprine (OR=2.6; 95% CI, 1.4-4.8). The prevalence of chronic anemia 12 months after HT was independent of the donor's sex, the recipient's age, the etiology of the recipient's heart failure, diabetes mellitus, mild-to-moderate graft rejection, cytomegalovirus infection, and angiotensin-converting enzyme inhibitor treatment. The presence of chronic anemia 12 months after HT did not influence either long-term survival (mean, 11.5 years with chronic anemia vs 13.0 years without) or actuarial survival. Conclusions. Post-HT chronic anemia is common, but improves with time and treatment. Predisposing factors for the condition 1 year post-HT include chronic renal failure, female sex, and immunosuppression with mycophenolate mofetil. The presence of chronic anemia does not appear to influence long-term survival.[Resumen] Introducción y objetivos. La información disponible sobre anemia crónica (AC) en pacientes con trasplante cardiaco (TC) es escasa y discordante. Nuestro objetivo fue estudiar la prevalencia de AC en pacientes post-TC, factores predisponentes de AC a 12 meses y su significa-do pronóstico a medio y largo plazo. Métodos. Análisis retrospectivo de pacientes con TC entre 1991 y 2005 (n = 457). AC fue definida como hemoglobina < 12 g/dl. Resultados. La prevalencia de AC post-TC fue del 75,5% a 1 mes, el 31% a los 12 meses y el 26,2% a los 120 meses, significativamente más prevalente en mujeres que en varones. Factores predisponentes de AC a 12 meses: insuficiencia renal crónica (IRC) leve-mode-rada (creatinina > 1,5 mg/dl) (odds ratio [OR] = 2,8; intervalo de confianza [IC] del 95%, 1,5-5); sexo femenino (OR = 6,4; IC del 95%, 3,1-13,2), e inmunosupresión con micofenolato mofetilo (MMF) respecto a azatioprina (OR = 2,6; IC del 95%, 1,4-4,8). La prevalencia de AC 1 año tras el TC no se relacionó con el sexo del donante, la edad del receptor, la cardiopatía del receptor, la diabetes mellitus, el rechazo leve o moderado del injerto (= 3A), infección por citomegalovirus o tratamiento con inhibidores de la enzima de conversión de angiotensina. Tener AC a 1 año del TC no supuso diferencias en la supervivencia a largo plazo (tiempo de vida medio con AC, 11,5 años y sin AC, 13 años) ni en la supervivencia actuarial. Conclusiones. La AC post-TC es un problema frecuente que mejora con el tiempo y el tratamiento. La IRC, el sexo femenino y la inmunosupresión con MMF predisponen a AC a los 12 meses del TC. Tener AC no parece influir en la supervivencia a largo plazo

    Food allergy in the Netherlands: differences in clinical severity, causative foods, sensitization and DBPCFC between community and outpatients

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    Background: It is unknown whether food allergy (FA) in an unselected population is comparable to those from an outpatient clinic population. Objective: To discover if FA in a random sample from the Dutch community is comparable to that of outpatients. Methods: This study was part of the Europrevall-project. A random sample of 6600 adults received a questionnaire. Those with symptoms to one of 24 defined priority foods were tested for sΙgE. Participants with a positive case history and elevated sIgE were evaluated by double-blind placebo-controlled food challenge (DBPCFC). Outpatients with a suspicion of FA were evaluated by questionnaire, sIgE and DBPCFC. Results: In the community, severe symptoms were reported less often than in outpatients (39.3% vs. 54.3%). Participants in the community were less commonly sensitized to any of the foods. When selecting only those with a probable FA (i.e. symptoms of priority food and elevation of sIgE to the respective food), no major differences were observed with respect to severity, causative foods, sensitization and DBPCFC between the groups. Conclusion: In the Netherlands, there are large differences in self-reported FA between community and outpatients. However, Dutch community and outpatients with a probable FA do not differ with respect to severity, causative foods, sensitization and DBPCFC-outcome

    Responses to salt stress in Juncus acutus and J. maritimus during seed germination and vegetative plant growth

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    [EN] Responses to increasing salinity, during seed germination and vegetative plant growth, were studied in two related species of Juncus, J. maritimus and J. acutus. In both species, germination was optimal in the absence of salt, reduced by about 50% in the presence of 200 mM NaCl, and completely inhibited by NaCl concentrations above 300 mM. Previous exposure of the seeds to salt, up to 500 mM NaCl, did not affect the germination capacity in J. acutus, and clearly enhanced it in J. maritimus. A concentration-dependent inhibition of plant growth was observed in the presence of NaCl for both species, together with the parallel accumulation of sodium ions in the leaves, as determined by cation exchange HPLC. Regarding the levels of divalent cations, in J. acutus Ca2+ and Mg2+ increased up to about two-fold in plants treated with 500 mM NaCl, as compared to control plants, whereas in J. maritimus they were three-to four-fold higher than in J. acutus in the absence of salt, and did not change significantly with increasing NaCl concentrations. These results suggest that Ca2+ and Mg2+ participate in defence mechanisms against salt stress, which would be constitutive in J. maritimus and salt-inducible in J. acutus.Boscaiu Neagu, MT.; Ballesteros Amat, G.; Naranjo Olivero, MA.; Vicente Meana, Ó.; Boira Tortajada, H. (2011). Responses to salt stress in Juncus acutus and J. maritimus during seed germination and vegetative plant growth. Plant Biosystems. 145(4):770-777. doi:10.1080/11263504.2011.628446S770777145
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