Phase transformation strengthening of high-temperature superalloys.

Decades of research has been focused on improving the high-temperature properties of nickel-based superalloys, an essential class of materials used in the hot section of jet turbine engines, allowing increased engine efficiency and reduced CO2 emissions. Here we introduce a new 'phase-transformation strengthening' mechanism that resists high-temperature creep deformation in nickel-based superalloys, where specific alloying elements inhibit the deleterious deformation mode of nanotwinning at temperatures above 700 °C. Ultra-high-resolution structure and composition analysis via scanning transmission electron microscopy, combined with density functional theory calculations, reveals that a superalloy with higher concentrations of the elements titanium, tantalum and niobium encourage a shear-induced solid-state transformation from the γ' to η phase along stacking faults in γ' precipitates, which would normally be the precursors of deformation twins. This nanoscale η phase creates a low-energy structure that inhibits thickening of stacking faults into twins, leading to significant improvement in creep properties.

[Alcohol consumption among students of a health area. Habits and beliefs]. / Consumo de alcohol en los escolares de un área de salud. Hábitos y creencias.

OBJECTIVES: 1. To describe the habits and conduct of school students (13-17 years old) around alcohol in the Cartagena Health Area. 2. To discover the factors underlying consumption. 3. To analyse beliefs and behaviour about consumption. DESIGN: Cross-sectional descriptive study. SETTING: Health area. PARTICIPANTS: 16,657 school students. Sample population (n = 1004). Large-group sampling (sampling unit: class-room), accuracy = 3%, CI = 95%, p = q = 50%, stratified by school and geographical area. MEASUREMENTS AND MAIN RESULTS: Anonymous, self-filled questionnaire (33 open and closed questions). SELECTION CRITERIA: attendance at class on the day of the questionnaire. VARIABLES: social, economic and cultural data on parents and students, course, type of family, alcohol consumption (starting age, access, individual habits, friends and family), beliefs about consumption, study profile of consumer. STATISTICAL ANALYSIS: description of variables, chi-squared test, t test, logistical regression. 99.2% filled in the questionnaire. Students' average age was 15.84 (SD, 1.21). 89.96% lived with their parents. 83.4% had consumed alcohol on some occasion, with no relationship to current consumption (p > 0.05). Starting age was 13.77 (SD, 1.78), 48.5% in discos/bars and 19% at home (p > 0.05). 47.5% had got drunk on some occasion (p > 0.05). 88.2% customarily drank alcohol mixed with other drinks (p > 0.05). 51.8% drank at week-ends (2.4% every day) (p > 0.05). 63.3% thought it easy to acquire drinks: 48.9% in supermarkets, 26.4% at petrol stations (p = 0.038). 71% of consumers agreed that "alcohol is a drug" (p = 0.005). 13% believed "it does not cause dependency" (p = 0.00001). 23.3% thought that it is not true to say "the person who does sport is healthier and does not take alcohol". CONCLUSIONS: The pattern of consumption is similar to that found in other autonomous communities, although in greater quantity and without differences in kind. Mean age of consumer: 15 years old. They usually drink alcohol mixed with other soft drinks, normally at week-ends. They are very ignorant of the effects of consumption.

Pterigium con mitomicina-C al 0, 02 por ciento: resultados y complicaciones / Pterygium with mytomicin-C to 0, 02 percent: results and complications

Objetivos: la finalidad de este trabajo es determinar la efectividad y las complicaciones asociadas al uso de mitomicina-C al 0,02 por ciento, intraoperatoria en la cirugía del pterigium. Pacientes y método: un total de 23 ojos en 23 pacientes fueron intervenidos por el mismo cirujano. Los criterios de inclusión consideraban pterigium uni o bilateral en pacientes menores de 40 años, o recidivantes en cualquier edad, que comprometían al menos 1,5 mm de la córnea desde el limbo, sin patología corneal concomitante. Como grupo control se consideraron 20 pacientes operados sin el antimitótico, con la misma técnica y por el mismo cirujano. Los pacientes fueron controlados a los 7, 30, 90 días y al año. Resultados: del total de pacientes operados con mitomicina al año, 4 pacientes de 23 presentaron recidivas (17,39 por ciento), entendidas como formaciones de 1,5 o más mm en la córnea, frente a 10 sobre 20 de los controles (50 por ciento). Las complicaciones fueron 1 caso de escleromalacia (4,35 por ciento), 5 casos de dehiscencias de sutura con formación de granuloma (21,74 por ciento), y 1 caso de quiste conjuntival tratado con reintervención a los 6 meses. Conclusiones: el uso de mitomicina al 0,02 por ciento en dosis única reduce la tasa de recidivas del pterigium con la técnica empleada, pero se asocia a una mayor incidencia de dehiscencias de sutura y granulomas