55 research outputs found

    Diseño e implementación de un banco de pruebas de inyectores de vehículos a diesel CRDI para la Escuela de Ingeniería Automotriz.

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    Este trabajo trata sobre el diseño e implementación de un banco de pruebas de inyectores de vehículos a diesel CRDI, con el objetivo de diagnosticar el funcionamiento o no de los inyectores de todos los vehículos de combustible diésel. En el país se ha ido incrementando en gran cantidad los vehículos con sistemas de inyección diesel como son: BOSCH, DELPHI, DENSO, siendo inapropiado el diagnostico de funcionamiento y análisis de averías de los inyectores. Este proyecto implementa el sistema de módulo controlador de pulsos electromagnéticos, el mismo que hace el trabajo de una ECU en un vehículo diésel, es decir da el mando para que el inyector a través de los pulsos, inyecte el combustible, abriendo y cerrando la tobera del inyector, con los datos establecidos en el módulo controlador. Además para que el inyector cumpla su función de inyección se incorpora un manómetro que hace la función de bomba para enviar presión al inyector y así poder comprobar si está cumpliendo o no con su funcionamiento normal y adecuado. Los estudios de los sistema de inyección directa en los vehículos a diesel, lleva a la invención, diseño, estudio técnico para la elaboración de un sistema de banco de pruebas, que genera pulsos electromagnéticos para controlar los inyectores (pulsos: 200, DUTY: ralentí: 40% y plena carga: 80%), implementando un diagnóstico más técnico, a menor tiempo y costo. Los resultados obtenidos son los siguientes: si los niveles de entrega y retorno son iguales: el inyector funciona regularmente pero debe ser reparado; si el nivel de entrega es mayor al nivel de retorno: el inyector funciona normalmente; si el nivel de retorno es mayor que el nivel de entrega hay una fuga y el vehículo no enciende; se recomienda antes de realizar un análisis de funcionamiento, utilizar equipos de seguridad y protección; además los inyectores deben ser reparados para funcionar correctamente, pero no necesariamente pueden solucionar el problema. Para un rendimiento óptimo y eficaz, todos los inyectores deben fluir a la misma cantidad de combustible y tener una buena atomización de combustible.This investigation is about the design and implementation of a test injector for diesel powered vehicles CRDI (Common Rail Diesel Injection), in order to diagnose if the injectors of all diesel powered vehicles work or not in a correct way. Vehicles with a diesel system have been increasing in a large number in the country; there are: BOSCH, DELPHI, and DENSO, but the operation diagnosis and injectors breakdown analysis are inappropriate. This project implements the electromagnetic pulse module controller system, which works as an ECU (Engine Control Unit) in a diesel vehicle; it means that the injector injects fuel by means of pulses, in this way it opens and closes the injector nozzle, with data established in the module controller, moreover, a pressure gauge is also implemented in order to fulfill the injection function which works a pump to send pressure to the injector, so this way you can check fi it fulfills or not with its normal and adequate operation. The surveys on direct injection system for diesel powered vehicles allow the creation, design, and technical research for the development of a test injector, which generates electromagnetic pulses to control the injector´s duty slow motion 40% and full charge 80%. This allowed implementing a more technical diagnosis with less time and cost. The results obtained are the following: if the fuel intake level and return level are similar: the injector works regularly, but it must be repaired, if the intake level is higher than the return level the injector works normally, if the return level is higher than the intake level, there is a leakage and the engine doesn´t start. Before making and operating analysis, it is recommended to use and wear safety and protection equipment and the injectors must also be repaired for a good operating, but they don´t necessarily solve the problem. For having an optimal and efficient performance, it is necessary that all the injectors have the same fuel flow to obtain a correct fuel atomization

    Ultrafast in cellulo photoinduced dynamics processes of the paradigm molecular light switch [Ru(bpy)2dppz]2+

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    An in cellulo study of the ultrafast excited state processes in the paradigm molecular light switch [Ru(bpy)2dppz]2+ by localized pump-probe spectroscopy is reported for the first time. The localization of [Ru(bpy)2dppz]2+ in HepG2 cells is verified by emission microscopy and the characteristic photoinduced picosecond dynamics of the molecular light switch is observed in cellulo. The observation of the typical phosphorescence stemming from a 3MLCT state suggests that the [Ru(bpy)2dppz]2+ complex intercalates with the DNA in the nucleus. The results presented for this benchmark coordination compound reveal the necessity to study the photoinduced processes in coordination compounds for intracellular use, e.g. as sensors or as photodrugs, in the actual biological target environment in order to derive a detailed molecular mechanistic understanding of the excited-state properties of the systems in the actual biological target environment

    Fingerprint multiplex CARS at high speed based on supercontinuum generation in bulk media and deep learning spectral denoising

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    We introduce a broadband coherent anti-Stokes Raman scattering (CARS) microscope based on a 2-MHz repetition rate ytterbium laser generating 1035-nm high-energy (≈µJ level) femtosecond pulses. These features of the driving laser allow producing broadband red-shifted Stokes pulses, covering the whole fingerprint region (400-1800 cm-1), employing supercontinuum generation in a bulk crystal. Our system reaches state-of-the-art acquisition speed (<1 ms/pixel) and unprecedented sensitivity of ≈14.1 mmol/L when detecting dimethyl sulfoxide in water. To further improve the performance of the system and to enhance the signal-to-noise ratio of the CARS spectra, we designed a convolutional neural network for spectral denoising, coupled with a post-processing pipeline to distinguish different chemical species of biological tissues

    Invited Article: Complex vibrational susceptibility by interferometric Fourier transform stimulated Raman scattering

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    We introduce interferometric (I) Fourier-transform (FT) stimulated Raman scattering (SRS) to measure the complex nonlinear vibrational susceptibility of molecules. The technique is a simple variation of FT-SRS, which was previously demonstrated to combine the very high sensitivity of single-channel lock-in detection with the spectral resolution afforded by FT spectroscopy. In IFT-SRS, a local oscillator, temporally anticipated with respect to the broadband pump pulse, enables the interferometric detection of both real and imaginary parts of the nonlinear susceptibility, whose spectrum is recorded in the time domain by scanning the delay of the local oscillator using a birefringent common-path interferometer. We apply IFT-SRS to record the complex vibrational response of different solvents and their mixtures. (C) 2018 Author(s)

    Label-free multimodal nonlinear optical microscopy reveals features of bone composition in pathophysiological conditions

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    Bone tissue features a complex microarchitecture and biomolecular composition, which determine biomechanical properties. In addition to state-of-the-art technologies, innovative optical approaches allowing the characterization of the bone in native, label-free conditions can provide new, multi-level insight into this inherently challenging tissue. Here, we exploited multimodal nonlinear optical (NLO) microscopy, including co-registered stimulated Raman scattering, two-photon excited fluorescence, and second-harmonic generation, to image entire vertebrae of murine spine sections. The quantitative nature of these nonlinear interactions allowed us to extract accurate biochemical, morphological, and topological information on the bone tissue and to highlight differences between normal and pathologic samples. Indeed, in a murine model showing bone loss, we observed increased collagen and lipid content as compared to the wild type, along with a decreased craniocaudal alignment of bone collagen fibres. We propose that NLO microscopy can be implemented in standard histopathological analysis of bone in preclinical studies, with the ambitious future perspective to introduce this technique in the clinical practice for the analysis of larger tissue sections

    Broadband stimulated Raman imaging based on multi-channel lock-in detection for spectral histopathology

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    Spontaneous Raman microscopy reveals the chemical composition of a sample in a label-free and non-invasive fashion by directly measuring the vibrational spectra of molecules. However, its extremely low cross section prevents its application to fast imaging. Stimulated Raman scattering (SRS) amplifies the signal by several orders of magnitude thanks to the coherent nature of the nonlinear process, thus unlocking high-speed microscopy applications that provide analytical information to elucidate biochemical mechanisms with subcellular resolution. Nevertheless, in its standard implementation, narrowband SRS provides images at only one frequency at a time, which is not sufficient to distinguish constituents with overlapping Raman bands. Here, we report a broadband SRS microscope equipped with a home-built multichannel lock-in amplifier simultaneously measuring the SRS signal at 32 frequencies with integration time down to 44 μs, allowing for detailed, high spatial resolution mapping of spectrally congested samples. We demonstrate the capability of our microscope to differentiate the chemical constituents of heterogeneous samples by measuring the relative concentrations of different fatty acids in cultured hepatocytes at the single lipid droplet level and by differentiating tumor from peritumoral tissue in a preclinical mouse model of fibrosarcoma

    Factors associated with cognitive impairment in Latin American older adults: A cross‐sectional observational study of COVID‐19 confinement

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    INTRODUCTION: The effects of COVID-19 confinement have been severe, especially in older adults. Therefore, we analyzed the factors associated with cognitive impairment (CI) in Latin America (LA). METHODS: We conducted a cross-sectional observational study with a total of 5245 older adults from 10 countries in LA. Measurement: We used the Telephone Montreal Cognitive Assessment (T-MoCA) and the Eight-item Informant Interview to Differentiate Aging and Dementia (AD8) scale. RESULTS: We found that age, depressive symptomatology, bone fractures, being widowed, having a family member with dementia, and unemployment were associated with an increased risk of CI. In contrast, higher education, hypertension with continuous treatment, quarantine, and keeping stimulating cognitive and physical activities were associated with a lower probability of CI. No significant association was found between suffering from diabetes or being retired and CI. DISCUSSION: It is essential to conduct follow-up studies on these factors, considering their relationship with CI and the duration of confinement

    Ontologías en disputa: Diálogos entre la antropología y la arqueología para la problematización de paisajes regionals

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    Objetivo/contexto: Hacia finales del siglo XX, el dualismo ontológico con el que antropólogos y arqueólogos nos hemos formado teórica y metodológicamente ha sido cuestionado y puesto en debate. En este contexto, nuestro objetivo es exponer críticamente los trabajos que se están realizando y que contribuyen a problematizar los paisajes enredados de existencias, materialidades, saberes, sentidos o prejuicios pasados y presentes, y con ello a restablecer el diálogo entre la antropología social y la arqueología. Metodología: Exponemos el estado actual de la apertura ontológica en clave latinoamericana. Problematizamos la noción de paisaje como concepto que permite diálogos teórico-metodológicos entre la antropología y la arqueología, así como con otras disciplinas. También presentamos ejes de comunicación y diálogo entre los artículos que forman parte del presente dossier para finalizar con los desafíos por delante en cuanto a traspasar fronteras disciplinarias, temporales y espaciales. Conclusiones: En contextos de históricas relaciones de poder, de profundas crisis socio-ambientales, los principales desafíos de la apertura ontológica serían: 1) generar referentes teóricos permeables a diversas disciplinas y saberes; 2) consolidar metodologías que integren lo etnográfico con lo arqueológico; 3) alentar diálogos constructivos hacia y con otras disciplinas y saberes, y 4) propiciar la comprensión del entramado político actual y la generación de políticas públicas que permitan diversas formas de relacionamiento con el entorno. Originalidad: El restablecimiento de diálogos entre la arqueología y la antropología social desde las aperturas ontológicas tiene el potencial de discutir cómo en determinados contextos se concretan y/o disputan paisajes y modos hegemónicos de habitar en el mundo, así como se problematizan los usos políticos del pasado y las políticas de uso del espacio y el ambiente.Objective/context: Towards the end of the 20th century, the ontological dualism with which anthropologists and archaeologists have trained us theoretically and methodologically has been questioned and debated. In this context, our objective is to critically expose the works that are being carried out and that contribute to problematizing the landscapes entangled with past and present existences, materialities, knowledge, senses or prejudices, and, with it, to re-establish the dialogue between social anthropology and archaeology. Methodology: We expose the current state of the ontological opening in Latin American code. We problematize the notion of landscape as a concept that allows theoretical-methodological dialogues between anthropology and archaeology, as well as with other disciplines. We also present axes of communication and dialogue between the articles that are part of this dossier, to end with the challenges ahead in terms of crossing disciplinary, temporal and spatial borders. Conclusions: In contexts of historical power relations, of deep socio-environmental crises, the main challenges for an ontological opening would be: 1) to generate theoretical referents permeable to various disciplines and fields of knowledge; 2) to consolidate methodologies that integrate the ethnographic with the archaeological; 3) to encourage constructive dialogues towards and with other disciplines and fields of knowledge; and 4) to propitiate the understanding of the current political framework and the generation of public policies that allow for diverse forms of relation with the environment. Originality: The re-establishment of dialogues between archaeology and social anthropology from ontological openings has the potential to discuss how, in certain contexts, landscapes and hegemonic ways of living are concretized and/or disputed, as well as the political uses of the past and the policies of use of space and the environment.Objetivo/contexto: No final do século XX, o dualismo ontológico com o qual antropólogos e arqueólogos se formaram teórica e metodologicamente vem sendo questionado e colocado em debate. Nesse contexto, nosso objetivo é expor criticamente os trabalhos que estão sendo realizados e que contribuem para problematizar as paisagens permeadas de existências, materialidades, saberes, sentidos ou preconceitos passados e presentes, e, com isso, reestabelecer o diálogo entre a antropologia social e a arqueologia. Metodologia: Expomos o estado atual da abertura ontológica no âmbito latino-americano. Problematizamos a noção de paisagem como conceito que permite diálogos teórico-metodológicos entre a antropologia e a arqueologia, assim como outras disciplinas. Também apresentamos eixos de comunicação e diálogo entre os artigos que fazem parte do presente dossiê para finalizar com os desafios que temos adiante sobre ultrapassar fronteiras disciplinares, temporais e espaciais. Conclusões: Em contextos de históricas relações de poder, de profundas crises socioambientais, os principais desafios para uma abertura ontológica seriam: 1) gerar referentes teóricos permeáveis a diversas disciplinas e saberes; 2) consolidar metodologias que integrem o etnográfico com o arqueológico; 3) promover diálogos construtivos com outras disciplinas e saberes; e 4) propiciar a compreensão da estrutura política atual e a geração de políticas públicas que permitam as diversas formas de relacionamentos com o ambiente. Originalidade: O reestabelecimento de diálogos entre a arqueologia e a antropologia social a partir das aberturas ontológicas tem o potencial de discutir como, em determinados contextos, se concretizam e/ou disputam paisagens e modos hegemônicos de habitar, bem como se problematizam os usos políticos do passado e as políticas de uso do espaço e do ambiente.Fil: Saldi, Leticia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Mafferra, Luis Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Barrientos Salinas, J. Alejandro. Universidad Mayor de San Andrés; Bolivi

    Contributions of mean and shape of blood pressure distribution to worldwide trends and variations in raised blood pressure: A pooled analysis of 1018 population-based measurement studies with 88.6 million participants

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    © The Author(s) 2018. Background: Change in the prevalence of raised blood pressure could be due to both shifts in the entire distribution of blood pressure (representing the combined effects of public health interventions and secular trends) and changes in its high-blood-pressure tail (representing successful clinical interventions to control blood pressure in the hypertensive population). Our aim was to quantify the contributions of these two phenomena to the worldwide trends in the prevalence of raised blood pressure. Methods: We pooled 1018 population-based studies with blood pressure measurements on 88.6 million participants from 1985 to 2016. We first calculated mean systolic blood pressure (SBP), mean diastolic blood pressure (DBP) and prevalence of raised blood pressure by sex and 10-year age group from 20-29 years to 70-79 years in each study, taking into account complex survey design and survey sample weights, where relevant. We used a linear mixed effect model to quantify the association between (probittransformed) prevalence of raised blood pressure and age-group- and sex-specific mean blood pressure. We calculated the contributions of change in mean SBP and DBP, and of change in the prevalence-mean association, to the change in prevalence of raised blood pressure. Results: In 2005-16, at the same level of population mean SBP and DBP, men and women in South Asia and in Central Asia, the Middle East and North Africa would have the highest prevalence of raised blood pressure, and men and women in the highincome Asia Pacific and high-income Western regions would have the lowest. In most region-sex-age groups where the prevalence of raised blood pressure declined, one half or more of the decline was due to the decline in mean blood pressure. Where prevalence of raised blood pressure has increased, the change was entirely driven by increasing mean blood pressure, offset partly by the change in the prevalence-mean association. Conclusions: Change in mean blood pressure is the main driver of the worldwide change in the prevalence of raised blood pressure, but change in the high-blood-pressure tail of the distribution has also contributed to the change in prevalence, especially in older age groups

    Rising rural body-mass index is the main driver of the global obesity epidemic in adults

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    Body-mass index (BMI) has increased steadily in most countries in parallel with a rise in the proportion of the population who live in cities(.)(1,2) This has led to a widely reported view that urbanization is one of the most important drivers of the global rise in obesity(3-6). Here we use 2,009 population-based studies, with measurements of height and weight in more than 112 million adults, to report national, regional and global trends in mean BMI segregated by place of residence (a rural or urban area) from 1985 to 2017. We show that, contrary to the dominant paradigm, more than 55% of the global rise in mean BMI from 1985 to 2017-and more than 80% in some low- and middle-income regions-was due to increases in BMI in rural areas. This large contribution stems from the fact that, with the exception of women in sub-Saharan Africa, BMI is increasing at the same rate or faster in rural areas than in cities in low- and middle-income regions. These trends have in turn resulted in a closing-and in some countries reversal-of the gap in BMI between urban and rural areas in low- and middle-income countries, especially for women. In high-income and industrialized countries, we noted a persistently higher rural BMI, especially for women. There is an urgent need for an integrated approach to rural nutrition that enhances financial and physical access to healthy foods, to avoid replacing the rural undernutrition disadvantage in poor countries with a more general malnutrition disadvantage that entails excessive consumption of low-quality calories.Peer reviewe
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