Organic films organized in nanostructured systems

En la presente Memoria se estudia la organización molecular de compuestos orgánicos, tales como lípidos, colorantes, y calixarenos anfifílicos en películas de Langmuir en la interfase aire-agua. También se estudia la influencia de la organización molecular sobre las propiedades fotofísicas y ópticas de dichos compuestos orgánicos. La Tesis doctoral está constituida por una Introducción general y por el conjunto de trabajos publicados, o pendientes de publicación, por el Doctorando. En la Introducción se hace una revisión general de la preparación de películas de Langmuir, de las técnicas de caracterización empleadas, y de los aspectos y modelos teóricos para la caracterización espectroscópica de las películas objeto de estudio. La relación de artículos se ha distribuido en tres capítulos atendiendo a los diferentes temas específicos en que dichos artículos pueden encuadrarse. Estudio del colapso de monocapas formadas por lípido y porfirina. En esta parte, el estudio del colapso de una película formada por DOMA y TSPP ha permitido establecer limitaciones al uso de la teoría NGC clásica en la formación de estructuras tridimensionales en la interfase. También ha arrojado luz sobre los factores que influyen en la reversibilidad del colapso de este tipo de películas, como son la línea de tensión de los dominios tridimensionales formados o la presencia de regiones donde persista la monocapa bidimensional al final del colapso de la película. Organización lateral en monocapas formadas por lípidos y colorantes. En esta parte se ha descubierto que la relación entre las áreas que ocupan las cadenas hidrófobas y los grupos polares cromóforos es un factor crucial en la formación de películas estables de mezclas de colorantes anfifílicos y lípidos, y en el control de la agregación de dichos colorantes en la interfase. Así mismo, se ha demostrado que este tipo de sistemas pueden formar estructuras ópticamente heterogéneas que se organizan en forma de cristal líquido bidimensional. Calixarenos anfifílicos y sus complejos de inclusión con fullereno en la interfase aire-agua. En esta última parte se muestra cómo se ha sintetizado un nuevo calixareno anfifílico monosustituido que, a diferencia de otros calixarenos, forma monocapas homogéneas y estables en la interfase aire-agua. También se ha sintetizado el complejo de inclusión de este calixareno y fullereno en proporción 2:1, CFC, que también es capaz de formar monocapas estables. Las monocapas formadas por ambos compuestos presentan morfologías diferentes, debido a la distinta orientación respecto a la interfase de las moléculas de calixareno en uno y otro sistema. Dado que el fullereno es un buen aceptor de electrones, el CFC tiene potencial para formar complejos supramoleculares más grandes con moléculas donadoras de electrones, como por ejemplo las porfirinas, en los que se pueda controlar la distancia entre las mismas, así como su orientación y agregación

Reversible collapse of insoluble monolayers

II Encuentro sobre nanociencia y nanotecnología de investigadores y tecnólogos de la Universidad de Córdoba. NANOUC

Colapso reversible de monocapas insolubles. Influencia de la línea de tensión de los dominios

II Encuentro sobre nanociencia y nanotecnología de investigadores y tecnólogos de la Universidad de Córdoba. NANOUC

Organización lateral de monocapas mixtas

III Encuentro sobre Nanociencia y Nanotecnología de Investigadores y Tecnólogos Andaluce

Molecular organization and effective energy transfer in iridium metallosurfactant-prophyrin assemblies embedded in Langmuir-Schaefer films

III Encuentro sobre Nanociencia y Nanotecnología de Investigadores y Tecnólogos Andaluce

Association of STAT4 with rheumatoid arthritis:A replication study in three European populations

OBJECTIVE: This study was undertaken to investigate the previously reported association of the STAT4 polymorphism rs7574865 with rheumatoid arthritis (RA) in 3 different European populations from Spain, Sweden, and The Netherlands, comprising a total of 2,072 patients and 2,474 controls. METHODS: Three different cohorts were included in the study: 923 RA patients and 1,296 healthy controls from Spain, 273 RA patients and 285 healthy controls from Sweden, and 876 RA patients and 893 healthy controls from The Netherlands. DNA from patients and controls was obtained from peripheral blood. Samples were genotyped for the STAT4 single-nucleotide polymorphism rs7574865 using a TaqMan 5'-allele discrimination assay. The chi-square test was performed to compare allele and genotype distributions. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated. RESULTS: We observed a significantly increased frequency of the minor T allele in RA patients compared with healthy controls in the Spanish population (24.8% versus 20.8%; P = 0.001, OR 1.26 [95% CI 1.09-1.45]). This association was confirmed in both the Swedish population (P = 0.03, OR 1.35 [95% CI 1.03-1.77]) and the Dutch population (P = 0.03, OR 1.45 [95% CI 1.21-1.73]). The overall P value for all 3 populations was 9.79 x 10(-6) (OR 1.25 [95% CI 1.13-1.37]). No association between rs7574865 and the presence of rheumatoid factor or anti-cyclic citrullinated peptide autoantibodies was observed. A meta-analysis of all published STAT4 associations revealed an OR of 1.25 (95% CI 1.19-1.33) (P = 1 x 10(-5)). CONCLUSION: Our findings indicate an association between the STAT4 polymorphism rs7574865 and RA in 3 different populations, from Spain, Sweden, and The Netherlands, thereby confirming previous data

Increased homocysteine plasma levels in breast cancer patients of a Mexican population

Aim: Hyperhomocysteinemia has been associated with different pathologies, including cardiovascular diseases, hypertension, diabetes, and breast cancer (BC). To examine the differences in total homocysteine (tHcy) plasma levels, we compared healthy women to BC patients from a Mexican population. Materials and Methods: The tHcy plasma levels were measured using high-performance liquid chromatography with a fluorescence detector in 89 female controls and 261 BC patients. Results: The observed plasma tHcy levels were significantly higher among the BC patients (11.1019 ± 5.9161 µmol/l) compared to the controls (9.1046 ± 1.3213 µmol/l) (p = 0.002), and these differences were evident when stratified by age (≥ 50 years old), menopause status, overweight and obesity, miscarriages, node metastases, progression, subtype classification (luminal, Her2 and triple negative) and nonresponse to chemotherapy. Conclusions: The tHcy plasma levels could be a good marker for the progression and chemosensitivity of BC in the analyzed sample from a Mexican population. Key Words: plasma levels, homocysteine, HPLC, breast cancer, Mexican population

Cut-offs and response criteria for the Hospital Universitario la Princesa Index (HUPI) and their comparison to widely-used indices of disease activity in rheumatoid arthritis

Objective To estimate cut-off points and to establish response criteria for the Hospital Universitario La Princesa Index (HUPI) in patients with chronic polyarthritis. Methods Two cohorts, one of early arthritis (Princesa Early Arthritis Register Longitudinal PEARL] study) and other of long-term rheumatoid arthritis (Estudio de la Morbilidad y Expresión Clínica de la Artritis Reumatoide EMECAR]) including altogether 1200 patients were used to determine cut-off values for remission, and for low, moderate and high activity through receiver operating curve (ROC) analysis. The areas under ROC (AUC) were compared to those of validated indexes (SDAI, CDAI, DAS28). ROC analysis was also applied to establish minimal and relevant clinical improvement for HUPI. Results The best cut-off points for HUPI are 2, 5 and 9, classifying RA activity as remission if =2, low disease activity if >2 and =5), moderate if >5 and <9 and high if =9. HUPI''s AUC to discriminate between low-moderate activity was 0.909 and between moderate-high activity 0.887. DAS28''s AUCs were 0.887 and 0.846, respectively; both indices had higher accuracy than SDAI (AUCs: 0.832 and 0.756) and CDAI (AUCs: 0.789 and 0.728). HUPI discriminates remission better than DAS28-ESR in early arthritis, but similarly to SDAI. The HUPI cut-off for minimal clinical improvement was established at 2 and for relevant clinical improvement at 4. Response criteria were established based on these cut-off values. Conclusions The cut-offs proposed for HUPI perform adequately in patients with either early or long term arthritis

Evidence for a mixed mass composition at the `ankle' in the cosmic-ray spectrum

We report a first measurement for ultra-high energy cosmic rays of the correlation between the depth of shower maximum and the signal in the water Cherenkov stations of air-showers registered simultaneously by the fluorescence and the surface detectors of the Pierre Auger Observatory. Such a correlation measurement is a unique feature of a hybrid air-shower observatory with sensitivity to both the electromagnetic and muonic components. It allows an accurate determination of the spread of primary masses in the cosmic-ray flux. Up till now, constraints on the spread of primary masses have been dominated by systematic uncertainties. The present correlation measurement is not affected by systematics in the measurement of the depth of shower maximum or the signal in the water Cherenkov stations. The analysis relies on general characteristics of air showers and is thus robust also with respect to uncertainties in hadronic event generators. The observed correlation in the energy range around the `ankle' at $\lg(E/{\rm eV})=18.5-19.0$ differs significantly from expectations for pure primary cosmic-ray compositions. A light composition made up of proton and helium only is equally inconsistent with observations. The data are explained well by a mixed composition including nuclei with mass $A > 4$. Scenarios such as the proton dip model, with almost pure compositions, are thus disfavoured as the sole explanation of the ultrahigh-energy cosmic-ray flux at Earth.Comment: Published version. Added journal reference and DOI. Added Report Numbe