Robustness of elastic properties in polymer nanocomposite films examined over the full volume fraction range.

Polymers with nanoparticle inclusions are attractive materials because physical properties can be tuned by varying size and volume fraction range. However, elastic behavior can degrade at higher inclusion fractions when particle-particle contacts become important, and sophisticated measurement techniques are required to study this crossover. Here, we report on the mechanical properties of materials with BaTiO3 nanoparticles (diameters < 10 nm) in a polymer (poly(methyl methacrylate)) matrix, deposited as films in different thickness ranges. Two well-known techniques, time and frequency domain Brillouin light scattering, were employed to probe the composition dependence of their elastic modulus. The time domain experiment revealed the biphasic state of the system at the highest particle volume fraction, whereas frequency domain Brillouin scattering provided comprehensive information on ancillary variables such as refractive index and directionality. Both techniques prove complementary, and can in particular be used to probe the susceptibility of elastic properties in polymer nanocomposites to aging.

Direction-dependent elastic properties and phononic behavior of PMMA/BaTiO3 nanocomposite thin films.

Determination of the anisotropic mechanical properties of nanostructured hybrid films is of great importance to improve fabrication and to enable reliable utility. Here, we employ spontaneous Brillouin light spectroscopy to record the phononic dispersion relation along the two symmetry directions in a supported PMMA (poly(methylmethacrylate))-BaTiO3 hybrid superlattice (SL) with a lattice constant of about 140 nm. Several dispersive elastic modes are resolved for in-plane wave propagation, whereas along the periodicity direction the SL opens a wide propagation stop band for hypersonic phonons and near UV photons both centered at about 280 nm. A thorough theoretical analysis based on the finite element method quantitatively captures the band diagrams along the two main symmetry directions, helps identify the large density mismatch effect on the unexpectedly low sound phase velocity, and reveals significant anisotropy of the SL elastic tensor. Phonon propagation is a sensitive index of the structure, density, and the mechanical moduli of nanocomposite films.

Directional elastic wave propagation in high-aspect-ratio photoresist gratings: liquid infiltration and aging.

Determination of the mechanical properties of nanostructured soft materials and their composites in a quantitative manner is of great importance to improve the fidelity in their fabrication and to enable the subsequent reliable utility. Here, we report on the characterization of the elastic and photoelastic parameters of a periodic array of nanowalls (grating) by the non-invasive Brillouin light scattering technique and finite element calculations. The resolved elastic vibrational modes in high and low aspect ratio nanowalls reveal quantitative and qualitative differences related to the two-beam interference lithography fabrication and subsequent aging under ambient conditions. The phononic properties, namely the dispersion relations, can be drastically altered by changing the surrounding material of the nanowalls. Here we demonstrate that liquid infiltration turns the phononic function from a single-direction phonon-guiding to an anisotropic propagation along the two orthogonal directions. The susceptibility of the phononic behavior to the infiltrating liquid can be of unusual benefits, such as sensing and alteration of the materials under confinement.

A new class of tunable hypersonic phononic crystals based on polymer-tethered colloids.

The design and engineering of hybrid materials exhibiting tailored phononic band gaps are fundamentally relevant to innovative material technologies in areas ranging from acoustics to thermo-optic devices. Phononic hybridization gaps, originating from the anti-crossing between local resonant and propagating modes, have attracted particular interest because of their relative robustness to structural disorder and the associated benefit to 'manufacturability'. Although hybridization gap materials are well known, their economic fabrication and efficient control of the gap frequency have remained elusive because of the limited property variability and expensive fabrication methodologies. Here we report a new strategy to realize hybridization gap materials by harnessing the 'anisotropic elasticity' across the particle-polymer interface in densely polymer-tethered colloidal particles. Theoretical and Brillouin scattering analysis confirm both the robustness to disorder and the tunability of the resulting hybridization gap and provide guidelines for the economic synthesis of new materials with deliberately controlled gap position and width frequencies.

Análisis descriptivo del tratamiento quirúrgico del cáncer de pulmón en los centros del sistema sanitario público de Andalucía. Proyecto vara II / Descriptive analysis of the surgical treatment of lung cancer at Public Health Hospitals in Andalusia: VARA Project II

Introducción: El cáncer de pulmón es el responsable de unas 3000 muertes cada año en Andalucía y, aunque la cirugía es el tratamiento de elección en estadios iniciales, menos del 20-25% son intervenidos. La Dirección del Plan Integral de Oncología de Andalucía (PIOA) realizó un estudio (Proyecto VARA I) sobre variabilidad y accesibilidad al tratamiento de radioterapia en 2003, observando una infrautilización manifiesta de este recurso en cáncer de pulmón. Esto motivó la puesta en marcha de un 2º estudio (VARA II) para evaluar el tratamiento locorregional, radioterapia y cirugía, del cáncer de pulmón en esta Comunidad. Material y métodos: Se evaluaron retrospectivamente las historias clínicas de los pacientes intervenidos en 2007 por cáncer de pulmón en los Hospitales Públicos de Andalucía. Se realizaron análisis descriptivos y de variabilidad entre los distintos equipos quirúrgicos. Resultados: Se evaluaron 418 pacientes, de los que 303 ofrecieron datos suficientes para el análisis. La edad media fue de 64 años (94% varones) con la siguiente distribución por estadios: I (60%), II (13%), III (21%), IV (6%). Se practicó tomografía de emisión de positrones (PET) en el 75% y mediastinoscopia en el 5%. La tasa de cirugía fue del 17% del total de casos esperados de cáncer de pulmón no células pequeñas. En el 97% de los casos se practicó linfadenectomía, la mayoría de ellas (72%) con un número de (..) (AU)

Introduction: Lung cancer is responsible of 3000 deaths every year in Andalusia. Although surgery is the elective treatment in early stages, less than 20-25% are operated on. The Direction of the Comprehensive Cancer Plan of Andalusia (PIOA) performed a study (VARA I Project) about variability and accessibility to radiation therapy in Andalusia in 2003, finding a clear infra utilisation in lung cancer. This motivated a second study (VARA II) to evaluate the locoregional treatment, both radiotherapy and surgery, of lung cancer in this region. Material and methods: Medical Records of patients operated in 2007 for lung cancer in Andalusian Public Hospitals were retrospectively evaluated. Descriptive analysis and studies of variability between surgical teams were performed. Results: Medical records of 418 patients were evaluated, 303 of them showing sufficient data for the analysis. Mean age was 64 (94% males), with the following stage distribution: I (60%), II (13%), III (21%), IV (6%). A PET was realized in 75% and mediastinoscopy in 5%. Surgery rate was 17% of the total expected cases of non small cell lung cancer. A lymphadenectomy was performed in 97%, the majority of them (72%) with less than 10 nodes resected. A good clinical and pathological concordance was demonstrated and low values of perioperative mortality (6%). Inter-hospitals variability study showed significant differences on histology, PET use, number of mediastinal nodes resected and reintervention rate. Discussion: The estimated surgical rate is similar to the published by other authors, although with a larger percentage of advanced stages III-IV. An important variability in patterns of care is demonstrated. Last, a low use of diagnostic mediastinoscopy is highlighted, while the use of PET for preoperative mediastinal evaluation is increasing, especially when the hospital owns the technique (AU)

Evidence-based estimation and radiotherapy utilisation rate in Andalusia.

INTRODUCTION: The objective of this study was to estimate the theoretical needs -based on evidence- of radiotherapy treatments (RDT) in Andalusia, compare these needs with actual use of RDT in 2006 and analyse their evolution from 2003. MATERIALS AND METHODS: Correlation between quantitative variables was analysed with Pearson's correlation coefficient. This dealt with differences between administered/estimated treatments and treatments carried out in years with the Student's t-distribution, and the Xi2 test among qualitative variables. RESULTS: In Andalusia, the evidence-based rate of cancer irradiation is 55%. Eighty-five percent of theoretical treatments were administered in 2006. From this group, 107% were in gynaecological tumours, 100% in breast cancer cases, 71% in head and neck cancer and 48% in lung cancers; differences in the last two conditions were significant (p<0.01). As for regional distribution, differences were reported with reference to irradiation rates (p<0.0002) and resource distribution. In the last three years, an increment of 17% was observed in treatments conducted in public hospitals. The rate increased from 61% (with regard to optimal values) to 85% in 2006; in a parallel way, an increment was seen in therapy units (from 22 to 26) and radiation oncologists (from 57 to 69). CONCLUSIONS: Despite the increment of irradiation rates seen in the last years, there is still a serious underutilisation of RDT for some cancer types (lung, head and neck cancer), as well as a great variability in the use of RDT between hospitals.

Evidence-based estimation and radiotherapy utilisation rate in Andalusia

INTRODUCTION: The objective of this study was to estimate the theoretical needs -based on evidence- of radiotherapy treatments (RDT) in Andalusia, compare these needs with actual use of RDT in 2006 and analyse their evolution from 2003. MATERIALS AND METHODS: Correlation between quantitative variables was analysed with Pearson's correlation coefficient. This dealt with differences between administered/estimated treatments and treatments carried out in years with the Student's t-distribution, and the Xi2 test among qualitative variables. RESULTS: In Andalusia, the evidence-based rate of cancer irradiation is 55%. Eighty-five percent of theoretical treatments were administered in 2006. From this group, 107% were in gynaecological tumours, 100% in breast cancer cases, 71% in head and neck cancer and 48% in lung cancers; differences in the last two conditions were significant (p<0.01). As for regional distribution, differences were reported with reference to irradiation rates (p<0.0002) and resource distribution. In the last three years, an increment of 17% was observed in treatments conducted in public hospitals. The rate increased from 61% (with regard to optimal values) to 85% in 2006; in a parallel way, an increment was seen in therapy units (from 22 to 26) and radiation oncologists (from 57 to 69). CONCLUSIONS: Despite the increment of irradiation rates seen in the last years, there is still a serious underutilisation of RDT for some cancer types (lung, head and neck cancer), as well as a great variability in the use of RDT between hospitals (AU)

[Non-small cell lung cancer. Survival after radiotherapy and prognostic factors]. / Carcinoma no microcítico de pulmón. Supervivencia y factores pronósticos del tratamiento radioterápico.

OBJECTIVE: To analyze the results of radiotherapy for non-small cell lung cancer and identify the clinical and therapeutic variables that might influence prognosis. PATIENTS AND METHODS: In a population base of 109 patients, 87 met the enrollment criteria. The patients received thoracic radiotherapy over the macroscopic tumor volume and lymph drainage areas, using conventional fractions. Systemic cytostatic therapy was also given to 61% of the patients. RESULTS: Staging was as follows: 33% (28/87) I and II, 20% (18/87) IIIA and 47% (41/87) IIIB. The mean radiotherapy dose was 66.7 Gy (95% CI, 65-67). Full clinical remission was achieved by 22% (18/87), half of whom later suffered recurrences. Partial remission was achieved by 26% (21/87). No response was observed in 52% (42/87). Statistically significant differences in actuarial survival rates were found for staging and tumor response. Mean survival for stages I and II was 29 months (95% CI, 19-39), for IIIA it was 22 (95% CI, 16-28) months, and for IIIB 16 months (95% CI, 12-20). The most common complications were cutaneous, esophageal and pulmonary, with a low incidence of grade 3 toxicity (less than 3%) and absence of grade 4. CONCLUSIONS: No differences in survival were observed for age, tumor location or histological type. Local control of the disease decisively influenced patient survival.

Carcinoma no microcítico de pulmón. Supervivencia y factores pronósticos del tratamiento radioterápico / Non-small cell lung cancer. Survival after radiotherapy and prognostic factors

Objetivo: Analizar los resultados de la radioterapia en el carcinoma no microcítico de pulmón y las características clínicas y terapéuticas que pueden influir en ellos. Pacientes y método: Sobre una base poblacional de 109 pacientes, 87 cumplieron los criterios de inclusión para el estudio. Recibieron radioterapia torácica sobre el volumen tumoral macroscópico y áreas de drenaje linfático, en fraccionamiento convencional. El 61 per cent recibió, además, tratamiento sistémico con citostáticos. Resultados: La distribución por estadios fue: 33 per cent (28/87) I + II; 20 per cent (18/87) IIIA, y 47 per cent (41/87) IIIB. La dosis media de radioterapia fue de 66,7 Gy (intervalo de confianza [IC] del 95 per cent, 65-67). Consiguió la remisión clínica completa el 22 per cent (18/87), de los cuales la mitad recidivó posteriormente; el 26 per cent (21/87) obtuvo una remisión parcial y el 52 per cent (42/87) no respondió. Se encontraron diferencias estadísticamente significativas en la supervivencia actuarial, según la estadificación y respuesta tumoral. La mediana de supervivencia para estadios I + II fue de 29 meses (IC del 95 per cent, 19-39); para los IIIA, de 22 meses (IC del 95 per cent, 16-28), y para los IIIB, de 16 meses (IC del 95 per cent, 12,20). Las complicaciones más frecuentes fueron las cutáneas, esofágicas y pulmonares, con una baja incidencia de toxicidad grado 3 (inferior al 3 per cent) y ausencia de grado 4.Conclusiones: No se encontraron diferencias en la supervivencia según la edad, localización tumoral y tipo histológico. El control local de la enfermedad influyó decisivamente en la supervivencia de estos pacientes (AU)