1,512 research outputs found

    The effect of combining bone morphogenetic proteins -2 and -6 on osteoblastic differentiation and bone

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    Bone morphogenetic proteins-2 and -7 (BMP-2 and -7) are the only two members of the BMP subfamily approved to date to be used in combination with collagen type I in orthopedic surgery, although other BMPs have proven to also be highly osteoinductive. All the osteogenic BMPs signal through Smad-1/-5/-8 phosphorylation, but they have different preferences for the BMP receptors they use. Very high supraphysiological doses of BMPs have been used in the clinics for the treatment of non-union fractures and spinal fusions. Besides the high cost of these treatments, safety concerns have been recently raised. Hence there is an active field in finding alternatives to the most classical collagen + BMP-2 system. The aim of this work was to study the effect of combining two osteogenic BMPs (-2 and -6) belonging to different groups within the subfamily, and with different affinities to the existing BMP receptors. Both the growth and osteoblastic differentiation of MC3T3-E1 mouse preosteoblasts and rat bone marrow-derived mesenchymal stem cells (MSCs) under these conditions were studied, as well as in vivo ectopic bone formation when the BMPs were combined with collagen type I sponges. We show that the effect of these two growth factors is additive and that their combination might be helpful to accelerate in vivo osteogenesis while reducing the amount of each individual BMP used.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Physiological Effects during Aerobatic Flights on Science Astronaut Candidates

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    Spaceflight is considered the last frontier in terms of science, technology, and engineering. But it is also the next frontier in terms of human physiology and performance. After more than 200,000 years humans have evolved under earth’s gravity and atmospheric conditions, spaceflight poses environmental stresses for which human physiology is not adapted. Hypoxia, accelerations, and radiation are among such stressors, our research involves suborbital flights aiming to develop effective countermeasures in order to assure sustainable human space presence. The physiologic baseline of spaceflight participants is subject to great variability driven by age, gender, fitness, and metabolic reserve. The objective of the present study is to characterize different physiologic variables in a population of STEM practitioners during an aerobatic flight. Cardiovascular and pulmonary responses were determined in Science Astronaut Candidates (SACs) during unusual attitude aerobatic flight indoctrination. Physiologic data recordings from 20 subjects participating in high-G flight training were analyzed. These recordings were registered by wearable sensor-vest that monitored electrocardiographic tracings (ECGs), signs of dysrhythmias or other electric disturbances during all the flight. The same cardiovascular parameters were also collected approximately 10 min pre-flight, during each high-G/unusual attitude maneuver and 10 min after the flights. The ratio (pre-flight/in-flight/post-flight) of the cardiovascular responses was calculated for comparison of interindividual differences. The resulting tracings depicting the cardiovascular responses of the subjects were compared against the G-loads (Gs) during the aerobatic flights to analyze cardiovascular variability aspects and fluid/pressure shifts due to the high Gs. Inflight ECG revealed cardiac variability patterns associated with rapid Gs onset in terms of reduced heart rate (HR) and some scattered dysrhythmic patterns (15% premature ventricular contractions-type) that were considered as triggered physiological responses to highG/unusual attitude training and some were considered as instrument artifact. Variation events were observed in subjects during the +Gz and –Gz maneuvers and these may be due to preload and afterload, sudden shift. Our data reveal that aerobatic flight influenced the breathing rate of the subject, due in part by the various levels of energy expenditure due to the increased use of muscle work during these aerobatic maneuvers. Noteworthy was the high heterogeneity in the different physiological responses among a relatively small group of SACs exposed to similar aerobatic flights with similar Gs exposures. The cardiovascular responses clearly demonstrated that SACs were subjected to significant flight stress. Routine ECG monitoring during high-G/unusual attitude flight training is recommended to capture pathology underlying dangerous dysrhythmias in suborbital flight safety. More research is currently being conducted to further facilitate the development of robust medical screening, medical risk assessment approaches, and suborbital flight training in the context of the evolving commercial human suborbital spaceflight industry. A more mature and integrative medical assessment method is required to understand the physiology state and response variability among highly diverse populations of prospective suborbital flight participants

    ¿Al fondo del escalafón?: un estado de la cuestión sobre el trabajo doméstico remunerado en el Perú

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    El sector de trabajadoras domésticas remuneradas ha enfrentado una discriminación histórica desproporcionada que pareciera estar relacionada con su particular composición sociodemográfica: mujeres jóvenes, de bajos recursos, bajo nivel educativo, provenientes de grupos étnicos marginados, trabajando en un 92.4% de los casos en condiciones de informalidad (INEI 2013). Además, a diferencia de otros trabajos, éste se realiza dentro de una residencia privada, donde resulta difícil que el Estado pueda regular y hacer cumplir los derechos y obligaciones establecidos por ley

    The Neuquén composite section: magnetostratigraphy and biostratigraphy of the marine lower Jurassic from the Neuquén basin (Argentina)

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    Paleomagnetic and biostratigraphic data from five marine sedimentary sections in the Argentine Neuquén basin have allowed to construct the Lower Jurassic Neuquén Composite Section. This composite section comprises 14 reversed and 11 normal polarity Zones, in relation to 17 Andean ammonite Assemblage Zones, spanning the Hettangian^Toarcian (Early Jurassic). It represents the first paleomagnetic data of Lower Jurassic marine successions in the Southern Hemisphere. The Neuquén composite Section was correlated to the International Mesozoic Polarity Time Scale which, for the Lower Jurassic, comprises 54 polarity Zones and 16 Standard ammonite Zones. The correlation between the regional and the international biomagnetostratigraphic scales supports but also refines the correlation between the Andean and Standard ammonite zonations. Correlation between the Neuquén composite Section and the polarity sequences recorded in each section helped to assign several unfossiliferous stratigraphical levels to the corresponding biozones.Facultad de Ciencias Naturales y Muse

    The Neuquén composite section: magnetostratigraphy and biostratigraphy of the marine lower Jurassic from the Neuquén basin (Argentina)

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    Paleomagnetic and biostratigraphic data from five marine sedimentary sections in the Argentine Neuquén basin have allowed to construct the Lower Jurassic Neuquén Composite Section. This composite section comprises 14 reversed and 11 normal polarity Zones, in relation to 17 Andean ammonite Assemblage Zones, spanning the Hettangian^Toarcian (Early Jurassic). It represents the first paleomagnetic data of Lower Jurassic marine successions in the Southern Hemisphere. The Neuquén composite Section was correlated to the International Mesozoic Polarity Time Scale which, for the Lower Jurassic, comprises 54 polarity Zones and 16 Standard ammonite Zones. The correlation between the regional and the international biomagnetostratigraphic scales supports but also refines the correlation between the Andean and Standard ammonite zonations. Correlation between the Neuquén composite Section and the polarity sequences recorded in each section helped to assign several unfossiliferous stratigraphical levels to the corresponding biozones.Facultad de Ciencias Naturales y Muse

    The Neuquén composite section: magnetostratigraphy and biostratigraphy of the marine lower Jurassic from the Neuquén basin (Argentina)

    Get PDF
    Paleomagnetic and biostratigraphic data from five marine sedimentary sections in the Argentine Neuquén basin have allowed to construct the Lower Jurassic Neuquén Composite Section. This composite section comprises 14 reversed and 11 normal polarity Zones, in relation to 17 Andean ammonite Assemblage Zones, spanning the Hettangian^Toarcian (Early Jurassic). It represents the first paleomagnetic data of Lower Jurassic marine successions in the Southern Hemisphere. The Neuquén composite Section was correlated to the International Mesozoic Polarity Time Scale which, for the Lower Jurassic, comprises 54 polarity Zones and 16 Standard ammonite Zones. The correlation between the regional and the international biomagnetostratigraphic scales supports but also refines the correlation between the Andean and Standard ammonite zonations. Correlation between the Neuquén composite Section and the polarity sequences recorded in each section helped to assign several unfossiliferous stratigraphical levels to the corresponding biozones.Facultad de Ciencias Naturales y Muse

    Control of mucocutaneous leishmaniasis, a neglected disease: results of a control programme in Satipo Province, Peru.

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    Mucocutaneous leishmaniasis (MCL) is an important health problem in many rural areas of Latin America, but there are few data on the results of programmatic approaches to control the disease. We report the results of a control programme in San Martin de Pangoa District, which reports one of the highest prevalences of MCL in Peru. For 2 years (2001--2002), the technicians at the health post were trained in patient case management, received medical support and were supplied with antimonials. An evaluation after 2 years showed the following main achievements: better diagnosis of patients, who were confirmed by microscopy in 34% (82/240) of the cases in 2001 and 60% of the cases (153/254) in 2002; improved follow-up during treatment: 237 of 263 (90%) patients who initiated an antimonial therapy ended the full treatment course; improved follow-up after treatment: 143 of 237 (60%) patients who ended their full treatment were correctly monitored during the required period of 6 (cutaneous cases) or 12 (mucosal cases) months after the end of treatment. These achievements were largely due to the human and logistical resources made available, the constant availability of medications and the close collaboration between the Ministry of Health, a national research institute and an international non-governmental organization. At the end of this period, the health authorities decided to register a generic brand of sodium stibogluconate, which is now in use. This should allow the treatment of a significant number of additional patients, while saving money to invest in other facets of the case management

    Apuntes de tecnología de fabricación de circuitos integrados monolíticos, de capa fina y de capa gruesa

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    Apuntes creados como apoyo a la asignatura "Tecnología de fabricación de circuitos integrados monolíticos", impartida en el curso 1974-1975
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