Coulomb's law modification in nonlinear and in noncommutative electrodynamics

We study the lowest-order modifications of the static potential for Born-Infeld electrodynamics and for the $\theta$-expanded version of the noncommutative U(1) gauge theory, within the framework of the gauge-invariant but path-dependent variables formalism. The calculation shows a long-range correction ($1/r^5$-type) to the Coulomb potential in Born-Infeld electrodynamics. However, the Coulomb nature of the potential (to order $e^2$) is preserved in noncommutative electrodynamics.Comment: 14 pages, 1 figur

Clinical and Immunological Factors That Distinguish COVID-19 From Pandemic Influenza A(H1N1)

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19), is a global health threat with the potential to cause severe disease manifestations in the lungs. Although COVID-19 has been extensively characterized clinically, the factors distinguishing SARS-CoV-2 from other respiratory viruses are unknown. Here, we compared the clinical, histopathological, and immunological characteristics of patients with COVID-19 and pandemic influenza A(H1N1). We observed a higher frequency of respiratory symptoms, increased tissue injury markers, and a histological pattern of alveolar pneumonia in pandemic influenza A(H1N1) patients. Conversely, dry cough, gastrointestinal symptoms and interstitial lung pathology were observed in COVID-19 cases. Pandemic influenza A(H1N1) was characterized by higher levels of IL-1RA, TNF-α, CCL3, G-CSF, APRIL, sTNF-R1, sTNF-R2, sCD30, and sCD163. Meanwhile, COVID-19 displayed an immune profile distinguished by increased Th1 (IL-12, IFN-γ) and Th2 (IL-4, IL-5, IL-10, IL-13) cytokine levels, along with IL-1β, IL-6, CCL11, VEGF, TWEAK, TSLP, MMP-1, and MMP-3. Our data suggest that SARS-CoV-2 induces a dysbalanced polyfunctional inflammatory response that is different from the immune response against pandemic influenza A(H1N1). Furthermore, we demonstrated the diagnostic potential of some clinical and immune factors to differentiate both diseases. These findings might be relevant for the ongoing and future influenza seasons in the Northern Hemisphere, which are historically unique due to their convergence with the COVID-19 pandemic

Double blind, randomized controlled trial, to evaluate the effectiveness of a controlled nitric oxide releasing patch versus meglumine antimoniate in the treatment of cutaneous leishmaniasis [NCT00317629]

BACKGROUND: Cutaneous Leishmaniasis is a worldwide disease, endemic in 88 countries, that has shown an increasing incidence over the last two decades. So far, pentavalent antimony compounds have been considered the treatment of choice, with a percentage of cure of about 85%. However, the high efficacy of these drugs is counteracted by their many disadvantages and adverse events. Previous studies have shown nitric oxide to be a potential alternative treatment when administered topically with no serious adverse events. However, due to the unstable nitric oxide release, the topical donors needed to be applied frequently, making the adherence to the treatment difficult. The electrospinning technique has allowed the production of a multilayer transdermal patch that produces a continuous and stable nitric oxide release. The main objective of this study is to evaluate this novel nitric oxide topical donor for the treatment of cutaneous leishmaniasis. METHODS AND DESIGN: A double-blind, randomized, double-masked, placebo-controlled clinical trial, including 620 patients from endemic areas for Leishmaniasis in Colombia was designed to investigate whether this patch is as effective as meglumine antimoniate for the treatment of cutaneous leishmaniasis but with less adverse events. Subjects with ulcers characteristic of cutaneous leishmaniasis will be medically evaluated and laboratory tests and parasitological confirmation performed. After checking the inclusion/exclusion criteria, the patients will be randomly assigned to one of two groups. During 20 days Group 1 will receive simultaneously meglumine antimoniate and placebo of nitric oxide patches while Group 2 will receive placebo of meglumine antimoniate and active nitric oxide patches. During the treatment visits, the medications will be daily administered and the presence of adverse events assessed. During the follow-up, the research group will visit the patients at days 21, 45, 90 and 180. The healing process of the ulcer, the health of the participants, recidivisms and/or reinfection will also be assessed. The evolution of the ulcers will be photographically registered. In case that the effectiveness of the patches is demonstrated, a novel and safe therapeutic alternative for one of the most important public health problems in many countries will be available to patients

Desarrollo tecnológico en ingeniería automotriz

El proceso de investigación y desarrollo tecnológico está directamente relacionado con una adecuada metodología de procesos industriales, que cada vez son más exigentes en competitividad, eficiencia energética y de normativas ambientales. Este libro contempla resultados de un proceso de investigación y desarrollo de nuevas técnicas aplicadas en el campo de la Ingeniería Automotriz desde cuatro aristas: eficiencia energética y contaminación ambiental, planificación del transporte, ingeniería del mantenimiento aplicada al transporte y desagregación tecnológica. Este libro conmemora 20 años de formación universitaria salesiana en el sector de transporte y recoge las experiencias y resultados obtenidos asociados con el desarrollo tecnológico en ingeniería automotriz. Para lograr este objetivo, se ha convocado a la comunidad científica, académica y profesionales de la industria automotriz a participar en la publicación. Cada capítulo fue sometido a revisión, evaluación y aprobación por un comité científico altamente calificado, proveniente de seis países: Colombia, Ecuador, España, Guinea Ecuatorial, México y Venezuela. Este trabajo ha sido posible gracias al gran apoyo de la Universidad Politécnica Salesiana (UPS sede Cuenca), Ecuador y Universidad de Los Andes (ULA)

First Sagittarius A* Event Horizon Telescope results. II. EHT and multiwavelength observations, data processing, and calibration

We present Event Horizon Telescope (EHT) 1.3 mm measurements of the radio source located at the position of the supermassive black hole Sagittarius A* (Sgr A*), collected during the 2017 April 5–11 campaign. The observations were carried out with eight facilities at six locations across the globe. Novel calibration methods are employed to account for Sgr A*'s flux variability. The majority of the 1.3 mm emission arises from horizon scales, where intrinsic structural source variability is detected on timescales of minutes to hours. The effects of interstellar scattering on the image and its variability are found to be subdominant to intrinsic source structure. The calibrated visibility amplitudes, particularly the locations of the visibility minima, are broadly consistent with a blurred ring with a diameter of ∼50 μas, as determined in later works in this series. Contemporaneous multiwavelength monitoring of Sgr A* was performed at 22, 43, and 86 GHz and at near-infrared and X-ray wavelengths. Several X-ray flares from Sgr A* are detected by Chandra, one at low significance jointly with Swift on 2017 April 7 and the other at higher significance jointly with NuSTAR on 2017 April 11. The brighter April 11 flare is not observed simultaneously by the EHT but is followed by a significant increase in millimeter flux variability immediately after the X-ray outburst, indicating a likely connection in the emission physics near the event horizon. We compare Sgr A*'s broadband flux during the EHT campaign to its historical spectral energy distribution and find that both the quiescent emission and flare emission are consistent with its long-term behavior.http://iopscience.iop.org/2041-8205Physic

First Sagittarius A* Event Horizon Telescope Results. II. EHT and Multiwavelength Observations, Data Processing, and Calibration

We present Event Horizon Telescope (EHT) 1.3 mm measurements of the radio source located at the position of the supermassive black hole Sagittarius A* (Sgr A*), collected during the 2017 April 5–11 campaign. The observations were carried out with eight facilities at six locations across the globe. Novel calibration methods are employed to account for Sgr A*'s flux variability. The majority of the 1.3 mm emission arises from horizon scales, where intrinsic structural source variability is detected on timescales of minutes to hours. The effects of interstellar scattering on the image and its variability are found to be subdominant to intrinsic source structure. The calibrated visibility amplitudes, particularly the locations of the visibility minima, are broadly consistent with a blurred ring with a diameter of ∼50 μas, as determined in later works in this series. Contemporaneous multiwavelength monitoring of Sgr A* was performed at 22, 43, and 86 GHz and at near-infrared and X-ray wavelengths. Several X-ray flares from Sgr A* are detected by Chandra, one at low significance jointly with Swift on 2017 April 7 and the other at higher significance jointly with NuSTAR on 2017 April 11. The brighter April 11 flare is not observed simultaneously by the EHT but is followed by a significant increase in millimeter flux variability immediately after the X-ray outburst, indicating a likely connection in the emission physics near the event horizon. We compare Sgr A*’s broadband flux during the EHT campaign to its historical spectral energy distribution and find that both the quiescent emission and flare emission are consistent with its long-term behavior

Metal-Organic Frameworks made of amino acids and adenine : chirality and hydrochromism /

Bibliografia.La presente Tesis ha sido enfocada en la síntesis de Polímeros de Coordinación (CPs) y Metal-organic frameworks (MOFs) a partir de ligandos basados en biomoléculas para la obtención de materiales nuevos y funcionales. Sobre esta premisa, la Tesis aborda dos líneas de investigación principales que han sido desarrolladas para alcanzar los objetivos propuestos: i) estudiar la influencia de la razón enantioméricos de dos ligandos quirales sobre la estructura y quiralidad en Metal-Organic Frameworks, y ii) el diseño y la síntesis de nuevos polímeros de coordinación basados en adenina, ligandos aromáticos tetracarboxílicos y metales de transición. En el Capítulo 1, mostramos un breve resumen a cerca de la química, los métodos de síntesis y las aplicaciones actuales de CPs/MOFs, como, por ejemplo, absorción de gases o catálisis, con énfasis en aquellos en los cuales se usan biomoléculas como bloques de construcción. Posteriormente, en el Capítulo 2, describimos los objetivos generales de nuestra tesis. El Capítulo 3 describe la importancia de la quiralidad como una importante propiedad en CPs/MOFs, y resume los resultados obtenido y publicados en el artículo "The influence of the enantiomeric ratio of an organic ligand on the structure and chirality of metal-organic frameworks", Chemical Communications, 2014, 50, 13829-13832. En este trabajo, hemos mostrado la importancia de la razón enantiomérica como variable relevante en la síntesis de MOFs porosos, y que puede ser tomada en cuenta como variable con resultados sorprendentes, la cual vii nos ha permitido obtener materiales porosos variando la razón enantiomérica. En el Capítulo 4, hemos tratado de desarrollar nuevos polímeros de coordinación basados en adenina usando ácidos aromáticos tetracarboxílicos, como ligandos auxiliares y Co(II). Lo resultados han sido publicados en el artículo titulado "Two New Adenine-based Co(II) Coordination Polymers: Synthesis, Crystal Structure, Coordination Modes and Reversible Hydrochromic Behavior", Crystal Growth and Design, 2015, 15, 3182-3189, donde hemos aprovechado de los cinco sitios potenciales de coordinación y mostrado la importancia de adenina como ligando rígido en la síntesis de polímeros funcionales.The present Thesis has been addressed to the synthesis of bio-related metal-organic frameworks and coordination polymers as novel and functional materials. On the basis of the above, two main lines were developed to reach the objectives proposed: i) study the influence of enantiomeric ratio of two chiral ligands over the structure and chirality in Metal-Organic Frameworks, and ii) the design and synthesis of novel coordination polymers based in nucleobase-adenine, aromatic tetracarboylate ligands and transition metals. In Chapter 1, we showed a brief review about Coordination Polymers (CPs)/Metal-Organic Frameworks (MOFs), their chemistry, synthetic methods and their current applications, as gas adsorption or catalysis, with emphasis in ones which use biomolecules as building blocks for the construction of coordination polymers. Then, general objectives of this Thesis are described in Chapter 2. Chapter 3 describes the importance of chirality as an important property in CPs/MOFs, and summarized the results obtained and reported in the article "The influence of the enantiomeric ratio of an organic ligand on the structure and chirality of metal-organic frameworks", Chemical Communications, 2014, 50, 13829-13832. In this work, we showed the importance of enantiomeric ratio as relevant variable in the synthesis of porous metal-organic frameworks, and as it might be introduced as variable with surprising results, which enabled us to obtain a porous material varying the enantiomeric ratio. v In Chapter 4, we aimed to develop new adenine-based coordination polymers using aromatic tetracarboxylic acids, as auxiliary linker and Co(II). We showed in the article titled "Two New Adenine-based Co(II) Coordination Polymers: Synthesis, Crystal Structure, Coordination Modes and Reversible Hydrochromic Behavior", Crystal Growth and Design, 2015, 15, 3182-3189, where we took advantage of its five potential coordination sites for metal binding, showing the relevance of adenine as rigid linker in the synthesis of functional coordination polymers

Antiagregantes plaquetarios: mecanismos de acción y riesgos asociados al uso Platelet antiaggregants: mechanisms of action and use asocied risks

Las Enfermedades Cardiovasculares son la principal causa de muerte en el mundo. Junto con los esfuerzos en disminuir los factores de riesgo cardiovascular, se recurre a diversos medicamentos para disminuir la morbimortalidad asociada a estas enfermedades, entre otros fármacos se utilizan, antihipertensivos, antidiabéticos, hipolipimiantes y antiagregantes plaquetarios. Dada la participación de las plaquetas, tanto en las etapas precoces de la aterogénesis como en la trombosis arterial, el uso de antiagregantes plaquetarios es muy relevante en la prevención primaria y secundaria de las trombosis arteriales. Los antiagregantes plaquetarios son utilizados en prevención primaria y secundaria de ECV. En esta revisión, se abordan diversos aspectos relativos a los antiagregantes, especialmente mecanismo de acción y riesgos asociados al uso durante los últimos 10 años. Como fuente bibliográfica se utilizó principalmente www.pubmed.com; y los términos utilizados en la búsqueda fueron: antiagregantes plaquetarios, aspirina, dipiridamol, clopidogrel, abciximab, entre otros; luego se buscaron los textos completos de los artículos que interesaban y además se utilizaron algunos libros de hematología.Cardiovascular diseases are the main cause of death in the world. Next to efforts to reduce the cardiovascular risk factors, several drugs are resorted to decrease morbimortality associated to these diseases: antihypertensive, antidiabetic, hypolipemiant and platelet antiaggregant drugs are used among others. Due to the participation of platelets, not only in the early stages of the atherogenesis but also in the artery thromboses, the use of platelet antiaggregant drugs is very relevant in the primary and secondary prevention of the artery thrombosis. In this review, after a brief description of the primary hemostasis, aspects of antiplatelet like mechanisms of action and use asocied risks during the last 10 years are adressed. Primarily literature source was www.pubmed.com. The terms used in the search were: platelet antiaggregant, aspirin, dipyridamole, clopidogrel, abciximab, among others, then we searched the full texts of articles of interest and also used some hematology books

Annual Optical Performance of a Solar CPC Photoreactor with Multiple Catalyst Support Configurations by a Multiscale Model

In this work, the seasonal and yearly optical performance of supported catalyst CPC solar photocatalytic reactors has been theoretically analyzed. A detailed model for the optical response of the anatase catalyst films is utilized, based on the characteristic matrix method, together with Monte Carlo ray tracing simulations. The catalyst is supported over glass tubes contained inside a larger glass tube that functions as receiver of the CPC reflector. Arrangements with four, five, and six tubes are considered. Overall, the four-tube scenario presents the worst performance of all, followed by the five-tube case. In general, the six-tube configuration is better. Nevertheless, important differences can be observed depending on the specific arrangement of tubes. The six-tube case surpasses the absorption rate of all the other configurations when the distance between tubes is extended. This configuration exhibits 27% increased yearly energy absorption with respect to the reference case and 47% with respect to the worst case scenario