Caracterización de tamaños de partícula: comparación entre difracción laser (ld) y microscopía electrónica de barrido (sem)

Two of the most significant properties of particles are size and shape; they often have direct influence on the materials behavior. Since the particulate systems are constituted by 3D particles of different size, the characterization of this property has to be given by a particle size distribution (PSD) . Among the most popular techniques for PSDs measurement, the image analysis (IA) presents some disadvantages: sampling errors, the analysis of only hundred or a few thousand particles to represent the whole population, the use a 2-D projected image of a 3-D particle and long analysis times. In contrast, the laser diffraction technique allows fast particulate systems characterization, processes a high number of particles per assay and provides highly reproducible results. However, LD provides no details about the particle morphology. Both techniques can be considered complementary, however several data interpretation problems appear whe n the results are compared. To do so, it is necessary to understand the meaning of the size descriptors given by each technique and under which conditions the comparison of results from different size analyzers can be done. In this sense, this work explores first the number of particles required to obtain reproducible PSDs by SEM. Then, it presents a comprehensive characterization of PVC particles by assessing a set of size and shape descriptors. The PSDs obtained by IA-SEM and LD were mathematically transformed to be compared. Finally, IA-SEM data was used to evaluate the convenience of using more than one size descriptor to represent the particles volume.Fil: Hegel, C.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Planta Piloto de Ingeniería Química (i); ArgentinaFil: Jones, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahia Blanca; ArgentinaFil: Cabrera, Fernanda Anabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Planta Piloto de Ingeniería Química (i); ArgentinaFil: Yañez, Maria Julia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahia Blanca; ArgentinaFil: Bucala, Veronica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Planta Piloto de Ingeniería Química (i); Argentin

9-[(E)-2-phenylethenyl]anthracene and 9-[(E)-2-(naphthalen-2-yl)ethenyl]anthracene as traps for singlet oxygen: photosensitized oxidation and photodynamic effect on Leishmania tarentolae parasites

Introducción: El oxígeno singulete es una especie reactiva que se obtiene mediante t r a n s f e r e n c i a e n e r g é t i c a u s a n d o u n fotosensibilizador. Su cuantificación directa requiere de instrumentación costosa, por lo cual es necesario recurrir a métodos indirectos que tengan suficiente selectividad y bajo costo. Estos procedimientos se basan en la interceptación química del oxígeno singulete produciendo una especie que se pueda detectar por métodos analíticos convencionales. En este artículo se describe la utilización del 9-[(E)-2-feniletenil] antraceno 1 (PEA) y del 9-[(E)-2-(naftalen-2-il) etenil]antraceno 2 (NEA), como alternativas viables y económicas para la cuantificación indirecta del oxígeno singulete, en medios acuosos. Su ventaja radica en la fácil detección de la desactivación de su fluorescencia una vez son oxidados por el oxígeno singulete. Materiales y Métodos: Los compuestos se sintetizaron y caracterizaron siguiendo procedimientos previamente reportados. Su capacidad para atrapar oxígeno singulete se determinó siguiendo su oxidación fotosensibilizada en solución de H2O/THF y en parásitos de Leishmania tarentolae, empleando azul de metileno o rosa bengala como fotosensibilizadores. Las muestras experimentales se iluminaron con una lámpara de emisión de luz visible, y se utilizaron métodos espectroscópicos (absorción UV-Vis, fluorescencia, RMN-1H) y espectrometría de masas para monitorear el atrapamiento y fotooxidación. Resultados y Discusión: Las pruebas espectroscópicas demostraron la capacidad que tienen los compuestos PEA 1 y NEA 2 para atrapar oxígeno singulete en solución acuosa y dentro de parásitos de L. tarentolae. Estudios de viabilidad parasitaria demuestran que PEA 1 es citotóxico en la oscuridad y cuando los cultivos son expuestos a la luz, mientras que NEA 2 no es citotóxico en la oscuridad, pero sí lo es cuando el cultivo es expuesto a la luz. En conclusión, los compuestos estudiados pueden servir como sondas para detectar y medir la producción de oxígeno singulete en medio acuoso y potencialmente en cultivos celulares, aunque es recomendable evaluar su actividad citotóxica en la oscuridad y bajo iluminación en estos casos.Introduction: Singlet oxygen is a reactive species obtained via energy transfer using a photosensitizer. Its direct quantification requires expensive instrumentation, so it is necessary to use indirect methods having sufficient selectivity and low cost. These procedures are based on the chemical interception of singlet oxygen producing a species that can be detected using conventional analytical methods. This article describes the utilization of 9-[(E)-2- phenylethenyl]anthracene 1 (PEA) and 9-[(E)-2- (naphtalen-2-yl)ethenyl]anthracene 2 (NEA) as suitable and economic alternatives for the indirect quantification of singlet oxygen in aqueous media. Their advantage is the easy detection of their fluorescence once they are oxidized by singlet oxygen. Materials and Methods: Compounds were synthesized and characterized following procedures previously reported. Their capacity to trap singlet oxygen was determined by monitoring their photosensitized oxidation in either a H2 O/THF solution or within Leishmania tarentolae parasites, utilizing methylene blue or rose bengal as photosensitizers. Experimental samples were illuminated with a lamp emitting visible light, while spectroscopical techniques (absorption, fluorescence, 1 H-NMR) and mass spectrometry were used to monitor trapping and photooxidation. Results and Discussion: Spectroscopical evidence demonstrates that both PEA 1 and NEA 2 are capable of trapping singlet oxygen in both aqueous media and within L. tarentolae parasites. Viability studies demonstrate that PEA 1 is cytotoxic in the dark and when parasite cultures were exposed to light, while NEA 2 does not show dark cytotoxicity, but is toxic when cultures were exposed to light. It can be concluded that both compounds under study may be utilized as probes to detect and quantify the production of singlet oxygen in aqueous media and potentially in cell cultures, although it is recommended to evaluate their cytotoxic activity both in the dark and upon light exposure in these cases

Challenges of and opportunities for protecting European soil biodiversity

Soil biodiversity and related ecosystem functions are neglected in most biodiversity assessments and nature conservation actions. We examined how society, and particularly policy makers, have addressed these factors worldwide with a focus on Europe and explored the role of soils in nature conservation in Germany as an example. We reviewed past and current global and European policies, compared soil ecosystem functioning in- and outside protected areas, and examined the role of soils in nature conservation management via text analyses. Protection and conservation of soil biodiversity and soil ecosystem functioning have been insufficient. Soil-related policies are unenforceable and lack soil biodiversity conservation goals, focusing instead on other environmental objectives. We found no evidence of positive effects of current nature conservation measures in multiple soil ecosystem functions in Europe. In German conservation management, soils are considered only from a limited perspective (e.g., as physicochemical part of the environment and as habitat for aboveground organisms). By exploring policy, evidence, and management as it relates to soil ecosystems, we suggest an integrative perspective to move nature conservation toward targeting soil ecosystems directly (e.g., by setting baselines, monitoring soil threats, and establishing a soil indicator system)

A VSA search for the extended Sunyaev-Zel'dovich Effect in the Corona Borealis Supercluster

We present interferometric imaging at 33 GHz of the Corona Borealis supercluster, using the extended configuration of the Very Small Array. A total area of 24 deg^2 has been imaged, with an angular resolution of 11 arcmin and a sensitivity of 12 mJy/beam. The aim of these observations is to search for Sunyaev-Zel'dovich (SZ) detections from known clusters of galaxies in this supercluster and for a possible extended SZ decrement due to diffuse warm/hot gas in the intercluster medium. We measure negative flux values in the positions of the ten richest clusters in the region. Collectively, this implies a 3.0-sigma detection of the SZ effect. In the clusters A2061 and A2065 we find decrements of approximately 2-sigma. Our main result is the detection of two strong and resolved negative features at -70+-12 mJy/beam (-157+-27 microK) and -103+-10 mJy/beam (-230+-23 microK), respectively, located in a region with no known clusters, near the centre of the supercluster. We discuss their possible origins in terms of primordial CMB anisotropies and/or SZ signals related to either unknown clusters or to a diffuse extended warm/hot gas distribution. Our analyses have revealed that a primordial CMB fluctuation is a plausible explanation for the weaker feature (probability of 37.82%). For the stronger one, neither primordial CMB (probability of 0.33%) nor SZ can account alone for its size and total intensity. The most reasonable explanation, then, is a combination of both primordial CMB and SZ signal. Finally, we explore what characteristics would be required for a filamentary structure consisting of warm/hot diffuse gas in order to produce a significant contribution to such a spot taking into account the constraints set by X-ray data.Comment: 16 pages, 10 figures. Accepted in MNRA

First results from the Very Small Array -- I. Observational methods

The Very Small Array (VSA) is a synthesis telescope designed to image faint structures in the cosmic microwave background on degree and sub-degree angular scales. The VSA has key differences from other CMB interferometers with the result that different systematic errors are expected. We have tested the operation of the VSA with a variety of blank-field and calibrator observations and cross-checked its calibration scale against independent measurements. We find that systematic effects can be suppressed below the thermal noise level in long observations; the overall calibration accuracy of the flux density scale is 3.5 percent and is limited by the external absolute calibration scale.Comment: 9 pages, 10 figures, MNRAS in press (Minor revisions

A study of the galaxy redshift distribution toward the cosmic microwave background cold spot in the Corona Borealis supercluster

We present a study of the spatial and redshift distributions of Sloan Digital Sky Survey (SDSS) galaxies toward the position of CrB-H, a very deep and extended decrement in the Cosmic Microwave Background (CMB), located within the Corona Borealis supercluster (CrB-SC). It was found in a survey with the Very Small Array (VSA) interferometer at 33 GHz, with a peak negative brightness temperature of -230 muK, and deviates 4.4-sigma from the Gaussian CMB (G\'enova-Santos et al.). Observations with the Millimeter and Infrared Testa Grigia Observatory (MITO) suggested that 25$^+21_-18% of this decrement may be caused by the thermal Sunyaev-Zel'dovich (tSZ) effect (Battistelli et al.). Here we investigate whether the galaxy distribution could be tracing either a previously unnoticed galaxy cluster or a Warm/Hot Intergalactic Medium (WHIM) filament that could build up this tSZ effect. We find that the projected density of galaxies outside Abell clusters and with redshifts 0.05<z<0.12 at the position of CrB-H is the highest in the area encompassed by the CrB-SC. Most of these galaxies are located around redshifts z=0.07 and z=0.11, but no clear connection in the form of a filamentary structure is appreciable in between. While the galaxy distribution at z=0.07 is sparse, we find evidence at z=0.11 of a galaxy group or a low-mass galaxy cluster. We estimate that this structure could produce a tSZ effect of ~ -18 muK. The remaining VSA signal of ~ -212 muK is still a significant 4.1-sigma deviation from the Gaussian CMB. However, the MITO error bar allows for a larger tSZ effect, which could be produced by galaxy clusters or superclusters beyond the sensitivity of the SDSS. Contributions from other possible secondary anisotropies associated with these structures are also discussed.Comment: 11 pages, 5 figures, 3 tables. Accepted in MNRA

Avaliação da adesão às diretrizes da Prática Clínica para Pneumonia associada à Ventilação Mecânica

Introducción: en el Hospital General Docente “Dr. Agostinho Neto” no se ha explorado el nivel de adherencia profesional a la Guía de práctica clínica ante la neumonía asociada a la ventilación mecánica.Objetivo: determinar el nivel deadherencia profesional a esta Guía durante el 2018.Método: durante el año 2018 se realizó un estudio descriptivo, prospectivo, aprobado por el Comité de Ética. Participaron ocho profesionales. Se emplearon métodos teóricos, empíricos y matemático-estadístico. Se estudiaron las siguientes variables: opinión de los profesionales sobre la guía y su evaluación, diagnóstico de la adherencia profesional a la guía.Resultados: el 100,0 % de los profesionales expresó un dominio de su contenido, utilidad y aseguraron estar adheridos a la guía. Cuatro (57,1 %) de los siete indicadores que se consideraron en la evaluación adherencia a la guía fueron evaluados en la categoría adecuado, uno (14,2 %) se evaluó en la categoría parcialmente adecuado y 2 (28,7 %) en la categoría poco adecuado. En general, la adherencia a la guía se evaluó en la categoría adecuada (85,7 %).Conclusiones: fue adecuada la adherencia profesional a la guía, la que estuvo limitada por la insuficiente estructura para el desarrollo del proceso de atención médica al paciente tratado con ventilación mecánica y de modo particular al afectado por este tipo de neumonía.Introduction: in the General Teaching Hospital “Dr. Agostinho Neto” the level of professional adherence to the clinical practice guideline before pneumonia associated with mechanical ventilation has not been explored.Objective: to determine the level of professional adherence to this guide during 2018.Method: during the year 2018 a descriptive, prospective study was approved, approved by the Ethics Committee. Eight professionals participated. Theoretical, empirical and mathematical-statistical methods were used. The following variables were studied: professional opinion on the guide and its evaluation, diagnosis of professional adherence to the guide.Results: the total of the professionals (100.0%) expressed a mastery of their content, usefulness and said they were adhering to the guide. Four (57.1%) of the seven indicators that were considered in the evaluation adherence to the guide were evaluated in the Adequate category, one (14.2%) was evaluated in the Partially Adequate category and 2 (28.7%) in the category Unsuitable. In general, adherence to the guide was assessed in the Adequate category (85.7%).Conclusions: professional adherence to the guide was adequate, which was limited by the insufficient structure for the development of the medical care process for patients treated with mechanical ventilation and particularly for those affected by this type of pneumonia.Introdução: no Hospital Geral de Ensino “Dr. Agostinho Neto” não explorou o nível de adesão profissional às diretrizes da prática clínica para pneumonia associada à ventilação mecânica.Objetivo: determinar o nível de adesão profissional a este guia em 2018.Método: durante o ano de 2018, foi aprovado um estudo descritivo e prospectivo, aprovado pelo Comitê de Ética. Oito profissionais participaram. Foram utilizados métodos teóricos, empíricos e matemático-estatísticos. Foram estudadas as seguintes variáveis: opinião profissional sobre o guia e sua avaliação, diagnóstico de adesão profissional ao guia.Resultados: o total dos profissionais (100,0%) manifestaram domínio do seu conteúdo, utilidade e afirmaram estar aderindo ao guia. Quatro (57,1%) dos sete indicadores considerados na adesão à avaliação foram avaliados na categoria Adequado, um (14,2%) foi avaliado na categoria Parcialmente Adequado e 2 (28,7%) na categoria Inadequado. De maneira geral, a adesão ao guia foi avaliada na categoria Adequado (85,7%).Conclusões: a adesão profissional ao guia foi adequada, limitada pela estrutura insuficiente para o desenvolvimento do processo de assistência médica aos pacientes tratados com ventilação mecânica e principalmente aos acometidos por esse tipo de pneumonia

Physical and respiratory therapy in the critically ill patient with obesity: a narrative review

Obesity has become increasingly prevalent in the intensive care unit, presenting a significant challenge for healthcare systems and professionals, including rehabilitation teams. Caring for critically ill patients with obesity involves addressing complex issues. Despite the well-established and safe practice of early mobilization during critical illness, in rehabilitation matters, the diverse clinical disturbances and scenarios within the obese patient population necessitate a comprehensive understanding. This includes recognizing the importance of metabolic support, both non-invasive and invasive ventilatory support, and their weaning processes as essential prerequisites. Physiotherapists, working collaboratively with a multidisciplinary team, play a crucial role in ensuring proper assessment and functional rehabilitation in the critical care setting. This review aims to provide critical insights into the key management and rehabilitation principles for obese patients in the intensive care unit

Searching for non-Gaussianity in the VSA data

We have tested Very Small Array (VSA) observations of three regions of sky for the presence of non-Gaussianity, using high-order cumulants, Minkowski functionals, a wavelet-based test and a Bayesian joint power spectrum/non-Gaussianity analysis. We find the data from two regions to be consistent with Gaussianity. In the third region, we obtain a 96.7% detection of non-Gaussianity using the wavelet test. We perform simulations to characterise the tests, and conclude that this is consistent with expected residual point source contamination. There is therefore no evidence that this detection is of cosmological origin. Our simulations show that the tests would be sensitive to any residual point sources above the data's source subtraction level of 20 mJy. The tests are also sensitive to cosmic string networks at an rms fluctuation level of $105 \mu K$ (i.e. equivalent to the best-fit observed value). They are not sensitive to string-induced fluctuations if an equal rms of Gaussian CDM fluctuations is added, thereby reducing the fluctuations due to the strings network to $74 \mu K$ rms . We especially highlight the usefulness of non-Gaussianity testing in eliminating systematic effects from our data.Comment: Minor corrections; accepted for publication to MNRA

Estimating the bispectrum of the Very Small Array data

We estimate the bispectrum of the Very Small Array data from the compact and extended configuration observations released in December 2002, and compare our results to those obtained from Gaussian simulations. There is a slight excess of large bispectrum values for two individual fields, but this does not appear when the fields are combined. Given our expected level of residual point sources, we do not expect these to be the source of the discrepancy. Using the compact configuration data, we put an upper limit of 5400 on the value of f_NL, the non-linear coupling parameter, at 95 per cent confidence. We test our bispectrum estimator using non-Gaussian simulations with a known bispectrum, and recover the input values.Comment: 17 pages, 16 figures, replaced with version accepted by MNRAS. Primordial bispectrum recalculated and figure 11 change