11 resultados para Neutral pH buffer

em Archivo Digital para la Docencia y la Investigación - Repositorio Institucional de la Universidad del País Vasco


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Azken urteotan eman diren kutsatzaile desberdinen gehiegizko isurpen edo erabilpena dela eta, lurzoruetan metal astunak metatu dira eta horrek , kate trofikoaren oinarrian dauden organismoen gainean k altea k sorrarazi d itu. Eisenia fetida zizarea espezie zent inela gisa erabili da lur entsegu ekotoxikologi koet an . Esperimentu honetan Eisenia fetida - ren jariakin zelomikoan dauden eta babes funtzioa duten zelomozitoak pH desberdinetara edo Kadmio bezalako metalera esposatzeak Neutral Red (NR) edo gorri neutro tindatzaile kationikoaren harreran eta fagoz itosi ahalmenean , eragina duen aztertu nahi izan da. Esperimentua in vitro egin zen 3R filosofia jarraituz. Alde batetik, pH desberdinen eragin ari dagokio nez gorri neutroaren harrera ( NRU ) entsegua n erantzun bimodal bat behatu zen eta beste alde bate tik, f agozitatzeko ahalmenari dagokiola zelomozitoak Eagle medioan kultibatzean ez zen aldaketa esangarria ikusi kadmioa ren, kontr olaren eta kontrol positi boaren artean. Bai ordea L - 1 5 medioarekin, non kontrol posit iboa k beste biak baino absorbantzia handiagoa erakutsi zuen. Emaitza hauek erakusten dute zelomozitoe n mintza gradualki kaltetzen doala pH neutrotik aldentzen doan heinean eta puntu batetik aurrera NRU emendatzen da zelomozito batzuen (amebozitoen) fagozitosia aktibatzen d el a ko .

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Published also as: Documento de Trabajo Banco de España 0504/2005.

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The main objective of this paper is to analyse the value of information contained in prices of options on the IBEX 35 index at the Spanish Stock Exchange Market. The forward looking information is extracted using implied risk-neutral density functions estimated by a mixture of two-lognormals and three alternative risk-adjustments: the classic power and exponential utility functions and a habit-based specification that allows for a counter-cyclical variation of risk aversion. Our results show that at four-week horizon we can reject the hypothesis that between October 1996 and March 2000 the risk-neutral densities provide accurate predictions of the distributions of future realisations of the IBEX 35 index at a four-week horizon. When forecasting through risk-adjusted densities the performance of this period is statistically improved and we no longer reject that hypothesis. All risk-adjusted densities generate similar forecasting statistics. Then, at least for a horizon of four-weeks, the actual risk adjustment does not seem to be the issue. By contrast, at the one-week horizon risk-adjusted densities do not improve the forecasting ability of the risk-neutral counterparts.

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Background: Lynch syndrome (LS) is an autosomal dominant inherited cancer syndrome characterized by early onset cancers of the colorectum, endometrium and other tumours. A significant proportion of DNA variants in LS patients are unclassified. Reports on the pathogenicity of the c.1852_1853AA>GC (p.Lys618Ala) variant of the MLH1 gene are conflicting. In this study, we provide new evidence indicating that this variant has no significant implications for LS. Methods: The following approach was used to assess the clinical significance of the p.Lys618Ala variant: frequency in a control population, case-control comparison, co-occurrence of the p.Lys618Ala variant with a pathogenic mutation, co-segregation with the disease and microsatellite instability in tumours from carriers of the variant. We genotyped p.Lys618Ala in 1034 individuals (373 sporadic colorectal cancer [CRC] patients, 250 index subjects from families suspected of having LS [revised Bethesda guidelines] and 411 controls). Three well-characterized LS families that fulfilled the Amsterdam II Criteria and consisted of members with the p.Lys618Ala variant were included to assess co-occurrence and co-segregation. A subset of colorectal tumour DNA samples from 17 patients carrying the p.Lys618Ala variant was screened for microsatellite instability using five mononucleotide markers. Results: Twenty-seven individuals were heterozygous for the p.Lys618Ala variant; nine had sporadic CRC (2.41%), seven were suspected of having hereditary CRC (2.8%) and 11 were controls (2.68%). There were no significant associations in the case-control and case-case studies. The p.Lys618Ala variant was co-existent with pathogenic mutations in two unrelated LS families. In one family, the allele distribution of the pathogenic and unclassified variant was in trans, in the other family the pathogenic variant was detected in the MSH6 gene and only the deleterious variant co-segregated with the disease in both families. Only two positive cases of microsatellite instability (2/17, 11.8%) were detected in tumours from p.Lys618Ala carriers, indicating that this variant does not play a role in functional inactivation of MLH1 in CRC patients. Conclusions: The p.Lys618Ala variant should be considered a neutral variant for LS. These findings have implications for the clinical management of CRC probands and their relatives.

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Temperature-sensitive poly(N-isopropylacrylamide) (PNIPA) nanohydrogels were synthesized by nanoemulsion polymerization in water-in-oil systems. Several cross-linking degrees and the incorporation of acrylic acid as comonomer at different concentrations were tested to produce nanohydrogels with a wide range of properties. The physicochemical properties of PNIPA nanohydrogels, and their relationship with the swelling-collapse behaviour, were studied to evaluate the suitability of PNIPA nanoparticles as smart delivery systems (for active packaging). The swelling-collapse transition was analyzed by the change in the optical properties of PNIPA nanohydrogels using ultraviolet-visible spectroscopy. The thermodynamic parameters associated with the nanohydrogels collapse were calculated using a mathematical approach based on the van't Hoff analysis, assuming a two-state equilibrium (swollen to collapsed). A mathematical model is proposed to predict both the thermally induced collapse, and the collapse induced by the simultaneous action of two factors (temperature and pH, or temperature and organic solvent concentration). Finally, van't Hoff analysis was compared with differential scanning calorimetry. The results obtained allow us to solve the problem of determining the molecular weight of the structural repeating unit in cross-linked NIPA polymers, which, as we show, can be estimated from the ratio of the molar heat capacity (obtained from the van't Hoff analysis) to the specific heat capacity (obtained from calorimetric measurements).

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Azken urte hauetan industriak izan duen garapenak, onura asko ekarri ditu, hala nola, bizi maila eta kalitatea gora egin dute. Baina dena ez dira alde onak, izan ere, prozesu honek, kutsagarriak eta oso konplexuak diren hondakinak sortu ditu. Kutsadura hau ez du soilik oreka ekologikoa n kalte egiten, izan ere, kutsadura hau dagoen guneetan ere eragin handia dauka. Hori dela eta , ingurumenaren babesa gero eta garrantzi handiagoa hartzen ari da. Horretarako, industriak sortzen dituen hondakinen tratamendurako prozesuetan, inbertsio ekonomiko handiak egin behar dira. Hau ez da soilik legea betetzeko egin behar, baizik eta, indus tria merkatuan dagoen konpetentzian toki on bat lortzeko oso garrantzitsua da. Jariakinen tratamenduaren xedea dituzten araztegiak duten arazo printzipala, jariakin hauetan dauden metal astunen presentzia da. Metal hauek, araztegi hauetan ematen diren pro zesu biologikoen zai ltasuna bermatzen dute eta animali, landare eta giza osasunean efektu toxikoak izaten dituzte. Baimenduta dauden kontzentrazioen limitea betetzeko, industriak normalean isurketan egin baino lehen, aurretratamendu bat egitera behartuta ikusten dira, toxikoak diren edo oso oldarkorrak diren produktuak kentzeko. Adibidez, Industria Hidrometalurgiakoak , oso kontzentrazio baxuetan metal astunak isurtzen ditu, baina kantitate hauek baimenduta daude, industria hau erabiltzen dituen emari handiak direla eta. Normalean hondakin industrialetatik kanpora isurt zen diren metal astunak , kontzentrazio baxuetan eg ot en dira . Honek, errentagarritasun positiboa du ten araztegi tekniken aplikazioa ahalbideratzen du. Kutsadura hau sortzen dituzten prozesu industrial mota asko existitzen direnez, metal hauek, oso diluituak dauden disoluzioetatik banatu behar dira. Horretara ko, metal baliotsuen errekuperazioa eta isurketa industrialaren legeak betetzea bermatzen duten, banaketa prozesuak sortu behar izan d ira. Jarraian, helburu hau duten teknika batzuk azaltzen dira

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Durante las dos grandes guerras mundiales España adoptó una posición de no beligerancia que conllevaría a unas consecuencias y un impacto muy diferente para la economía española en uno y en otro conflicto. Por un lado España se presenta ante la Primera Guerra Mundial como una economía totalmente atrasada y agraria, mientras que con el estallido del conflicto supo aprovechar las necesidades del momento, permitiendo de esta manera un fuerte enriquecimiento. Por otro lado, en la Segunda Guerra Mundial España se encontraba totalmente destruida y con una fuerte inestabilidad, lo cual supuso que junto con las medidas autárquicas de la dictadura conllevaran a un periodo de penuria. IDIOMA: CASTELLANO

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Temperature-sensitive poly(N-isopropylacrylamide) (PNIPA) nanohydrogels were synthesized by nanoemulsion polymerization in water-in-oil systems. Several cross-linking degrees and the incorporation of acrylic acid as comonomer at different concentrations were tested to produce nanohydrogels with a wide range of properties. The physicochemical properties of PNIPA nanohydrogels, and their relationship with the swelling-collapse behaviour, were studied to evaluate the suitability of PNIPA nanoparticles as smart delivery systems (for active packaging). The swelling-collapse transition was analyzed by the change in the optical properties of PNIPA nanohydrogels using ultraviolet-visible spectroscopy. The thermodynamic parameters associated with the nanohydrogels collapse were calculated using a mathematical approach based on the van't Hoff analysis, assuming a two-state equilibrium (swollen to collapsed). A mathematical model is proposed to predict both the thermally induced collapse, and the collapse induced by the simultaneous action of two factors (temperature and pH, or temperature and organic solvent concentration). Finally, van't Hoff analysis was compared with differential scanning calorimetry. The results obtained allow us to solve the problem of determining the molecular weight of the structural repeating unit in cross-linked NIPA polymers, which, as we show, can be estimated from the ratio of the molar heat capacity (obtained from the van't Hoff analysis) to the specific heat capacity (obtained from calorimetric measurements).

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Artículo científico Inorg. Chem. 2013, 52, 8074−8081

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El objetivo de este trabajo es comprobar la homodimerización del dominio PH de la PDK1 in vitro.