Magnetic and Viscoelastic Response of Magnetorheological Elastomers Based on a Combination of Iron Nano- and Microparticles.

In this paper, we discuss the creation of a hybrid magnetorheological elastomer that combines nano- and microparticles. The mixture contained 45 wt.% fillers, with combinations of either 0% nanoparticles and 100% microparticles or 25% nanoparticles and 75% microparticles. TGA and FTIR testing confirmed the materials' thermal and chemical stability, while an SEM analysis determined the particles' size and morphology. XRD results were used to determine the crystal size of both nano- and microparticles. The addition of reinforcing particles, particularly nanoparticles, enhanced the stiffness of the composite materials studied, but their overall strength was only minimally affected. The computed interaction parameter relative to the volume fraction was consistent with the previous literature. Furthermore, the study observed a magnetic response increment in composite materials reinforced with nanoparticles above 30 Hz. The isotropic material containing only microparticles had a lower storage modulus than the isotropic sample with nanoparticles without a magnetic field. However, when a magnetic field was applied, the material with only microparticles exhibited a higher storage modulus than the samples with nanoparticles.

Imagery in the entropic associative memory.

The Entropic Associative Memory is a novel declarative and distributed computational model of associative memory. The model is general, conceptually simple, and offers an alternative to models developed within the artificial neural networks paradigm. The memory uses a standard table as its medium, where the information is stored in an indeterminate form, and the entropy plays a functional and operation role. The memory register operation abstracts the input cue with the current memory content and is productive; memory recognition is performed through a logical test; and memory retrieval is constructive. The three operations can be performed in parallel using very few computing resources. In our previous work we explored the auto-associative properties of the memory and performed experiments to store, recognize and retrieve manuscript digits and letters with complete and incomplete cues, and also to recognize and learn phones, with satisfactory results. In such experiments a designated memory register was used to store all the objects of the same class, whereas in the present study we remove such restriction and use a single memory register to store all the objects in the domain. In this novel setting we explore the production of emerging objects and relations, such that cues are used not only to retrieve remembered objects, but also related and imaged objects, and to produce association chains. The present model supports the view that memory and classification are independent functions both conceptually and architecturally. The memory system can store images of the different modalities of perception and action, possibly multimodal, and offers a novel perspective on the imagery debate and computational models of declarative memory.

Weighted entropic associative memory and phonetic learning.

The Entropic Associative Memory (EAM) holds declarative but distributed representations of remembered objects. These are characterized as functions from features to discrete values in an abstract amodal space. Memory objects are registered or remembered through a declarative operation; memory recognition is defined as a logical test and cues of objects not contained in the memory are rejected directly without search; and memory retrieval is a constructive operation. In its original formulation, the content of basic memory units or cells was either on or off, hence all stored objects had the same weight or strength. In the present weighted version (W-EAM) we introduce a basic learning mechanism to the effect that the values of the cells used in the representation of an object are reinforced by the memory register operation. As memory cells are shared by different representations, the corresponding associations are reinforced too. The memory system supports a second form of learning: the distributed representation generalizes and renders a large set of potential or latent units that can used for recognizing novel inputs, which can in turn be used for improving the performance of both the deep neural networks used for modelling perception and action, and of the memory operations. This process can be performed recurrently in open-ended fashion and can be used in long term learning. An experiment in the phonetic domain using the Mexican Spanish DIMEx100 Corpus was carried out. This corpus was collected in a controlled noise-free environment, and was transcribed manually by human trained phoneticians, but consists of a relatively small number of utterances. DIMEx100 was used to produced the initial state of the perceptual and motor modules, and for testing the performance of the memory system at such state. Then the incremental learning cycle was modelled using the Spanish CIEMPIESS Corpus, consisting of a very large number of noisy untagged speech utterances collected from radio and TV. The results support the viability of the Weighted Entropic Associative Memory for modelling cognitive processes, such as phonetic representation and learning, for the construction of applications, such as speech recognition and synthesis, and as a computational model of natural memory.

Entropic associative memory for manuscript symbols.

Manuscript symbols can be stored, recognized and retrieved from an entropic digital memory that is associative and distributed but yet declarative; memory retrieval is a constructive operation, memory cues to objects not contained in the memory are rejected directly without search, and memory operations can be performed through parallel computations. Manuscript symbols, both letters and numerals, are represented in Associative Memory Registers that have an associated entropy. The memory recognition operation obeys an entropy trade-off between precision and recall, and the entropy level impacts on the quality of the objects recovered through the memory retrieval operation. The present proposal is contrasted in several dimensions with neural networks models of associative memory. We discuss the operational characteristics of the entropic associative memory for retrieving objects with both complete and incomplete information, such as severe occlusions. The experiments reported in this paper add evidence on the potential of this framework for developing practical applications and computational models of natural memory.

Soft Tissue Hybrid Model for Real-Time Simulations.

In this article, a recent formulation for real-time simulation is developed combining the strain energy density of the Spring Mass Model (SMM) with the equivalent representation of the Strain Energy Density Function (SEDF). The resulting Equivalent Energy Spring Model (EESM) is expected to provide information in real-time about the mechanical response of soft tissue when subjected to uniaxial deformations. The proposed model represents a variation of the SMM and can be used to predict the mechanical behavior of biological tissues not only during loading but also during unloading deformation states. To assess the accuracy achieved by the EESM, experimental data was collected from liver porcine samples via uniaxial loading and unloading tensile tests. Validation of the model through numerical predictions achieved a refresh rate of 31 fps (31.49 ms of computation time for each frame), achieving a coefficient of determination R2 from 93.23% to 99.94% when compared to experimental data. The proposed hybrid formulation to characterize soft tissue mechanical behavior is fast enough for real-time simulation and captures the soft material nonlinear virgin and stress-softened effects with high accuracy.

Study of the Evolution of the Plastic Zone and Residual Stress in a Notched T-6061 Aluminum Sample.

Using experimental measurements and numerical computations, this paper focuses on studying the evolution of the plastic zone and how the residual stresses change in a notched T-6061 aluminum sample. Before the crack initiation, digital image measurements were taken to visualize the evolution of the plastic zone. After the sample was fractured, the material microstructure and the residual stresses around the cracked zone were characterized through optical microscopy and X-ray diffractometry. This article describes in detail how the plastic zone evolved around the notch before the crack initiation and shows the close agreement between experimental and numerical data during the load increment. The surface residual stress values around the tip of the notched sample were also measured and computed to give a better understanding of the affected region during the fracture process.

An entropic associative memory.

Natural memories are associative, declarative and distributed, and memory retrieval is a constructive operation. In addition, cues of objects that are not contained in the memory are rejected directly. Symbolic computing memories resemble natural memories in their declarative character, and information can be stored and recovered explicitly; however, they are reproductive rather than constructive, and lack the associative and distributed properties. Sub-symbolic memories developed within the connectionist or artificial neural networks paradigm are associative and distributed, but lack the declarative property, the capability of rejecting objects that are not included in the memory, and memory retrieval is also reproductive. In this paper we present a memory model that sustains the five properties of natural memories. We use Relational-Indeterminate Computing to model associative memory registers that hold distributed representations of individual objects. This mode of computing has an intrinsic computing entropy which measures the indeterminacy of representations. This parameter determines the operational characteristics of the memory. Associative registers are embedded in an architecture that maps concrete images expressed in modality specific buffers into abstract representations and vice versa. The framework has been used to model a visual memory holding the representations of hand-written digits. The system has been tested with a set of memory recognition and retrieval experiments with complete and severely occluded images. The results show that there is a range of entropy values, not too low and not too high, in which associative memory registers have a satisfactory performance. The experiments were implemented in a simulation using a standard computer with a GPU, but a parallel architecture may be built where the memory operations would take a very reduced number of computing steps.

Guía de práctica clínica para el tratamiento de la enfermedad de Crohn en población adulta / Clinical practice guidelines for the treatment of Crohn's disease in the adult population

Resumen Objetivo: La enfermedad de Crohn es un trastorno inflamatorio idiopático de etiología desconocida con características genéticas, inmunológicas e influencias del medio ambiente. La incidencia y la prevalencia de la enfermedad de Crohn han aumentado en Colombia. El tratamiento de estos pacientes no es fácil y ha evolucionado en los últimos años; por lo tanto, es necesario desarrollar una guía de práctica clínica en Colombia, orientada al tratamiento de esta compleja enfermedad, para unificar criterios. Materiales y métodos: Esta guía fue desarrollada por un equipo multidisciplinario con apoyo de la Asociación Colombiana de Gastroenterología, el Grupo Cochrane ITS y el Instituto de Investigaciones Clínicas de la Universidad Nacional de Colombia. Se desarrollaron preguntas clínicas relevantes a la entidad y se realizó la búsqueda de guías nacionales e internacionales en bases de datos especializadas. Las guías existentes fueron evaluadas en términos de calidad y aplicabilidad. El Grupo Cochrane realizó la búsqueda sistemática de la literatura. Las tablas de evidencia y recomendaciones fueron realizadas usando la metodología GRADE. Resultados: Se realizó una guía de práctica clínica basada en la evidencia, para el tratamiento tanto médico como quirúrgico de la enfermedad de Crohn en población adulta en Colombia. Se diseñaron algoritmos de manejo teniendo en cuenta la actividad, el comportamiento y la localización de la enfermedad. Conclusiones: Se estableció que una adecuada evaluación clínica, endoscópica e imagenológica, así como una estratificación de riesgo individual son importantes para el manejo, y se especificaron las indicaciones para el adecuado tratamiento tanto médico como quirúrgico de estos pacientes.

Abstract Objective: Crohn's disease is an idiopathic inflammatory disorder of unknown origin, influenced by genetic, immunological, and environmental factors. The incidence and prevalence of Crohn's disease have increased in Colombia. The treatment of these patients is not easy and has improved in recent years. Therefore, it is necessary to develop the Colombian Clinical Practice Guideline to guide the treatment of this complex disease and unify criteria. Materials and methods: The present guideline was carried out by a multidisciplinary team with support from the Asociación Colombiana de Gastroenterología, the Cochrane ITS Team, and the Clinical Research Institute of the Universidad Nacional de Colombia. Clinical questions regarding this disease were developed, and national and international guidelines were searched in specialized databases. The existing guidelines were evaluated in terms of quality and applicability. The Cochrane Group conducted a systematic search of the existing literature. Evidence tables were elaborated, and recommendations were made using the GRADE methodology. Results: An evidence-based clinical practice guideline was developed for the medical and surgical treatment of Crohn's disease in the adult population in Colombia. Treatment algorithms were designed, taking into account the activity, behavior, and location of the disease. Conclusions: It was established that proper clinical, endoscopic, and imaging assessment, as well as individual risk stratification, are important for treatment. Also, the indications for adequate medical and surgical treatment of these patients were specified.

Investigating the Mullins Effect and Energy Dissipation in Magnetorheological Polyurethane Elastomers.

The aim of this article was to investigate the mechanical performance of magnetorheological polyurethane elastomers reinforced with different concentrations of carbonyl iron microparticles (CIPs) in which stress softening, energy dissipation, residual strains, microparticles orientation, and magnetic flux density effects will be considered. Other aspects, such as the determination of the dissipated energy during cyclic loading and unloading, were investigated by considering a pseudo-elastic network model that takes into account residual strains, magnetic field intensity, and the isotropic and anisotropic material behavior. Theoretical predictions confirmed that the material shear modulus becomes sensitive not only for higher concentrations of CIPs added into the elastomer material matrix, but also to the magnetic flux intensity that induces attractive forces between CIPs and to the strong bonds between these and the elastomer matrix. It was also found that the addition of CIPs when embedded into the polymer matrix with a predefined orientation enhances the material shear modulus as well as its capacity to dissipate energy when subjected to magnetic flux density in loading and unloading directions.

Procedimientos endoscópicos y pandemia COVID-19: consideraciones básicas / Basic considerations regarding endoscopic procedures during the COVID-19 pandemic

El SARS-Cov-2 es un coronavirus productor de la enfermedad COVID-19. Esta inició en Wuhan, capital de la provincia Hubei, China. En menos de cuatro meses la enfermedad se dispersó por el mundo, lo que dio origen a miles de muertes. La Organización Mundial de la Salud (OMS) la ha declarado pandemia. La humanidad está consternada, múltiples gobiernos han obligado al aislamiento total, con éxito variable debido a la negligencia de parte de la comunidad. En muchas ciudades las instituciones y el personal sanitario no son suficientes para atender la catástrofe. El aislamiento es la única estrategia eficaz para detener el crecimiento logarítmico de COVID-19. El motivo científico del aislamiento es que más del 60 % de los contagios surgen de personas asintomáticas. La enfermedad no solo produce síntomas respiratorios. El SARS-Cov-2, además, puede producir náuseas, dolor abdominal, vómito, diarrea, anosmia y ageusia. El 50% de los infectados pueden tener síntomas digestivos, que incluso preceden a los respiratorios. La ruta fecal-oral trasmite el virus, aún sin diarrea. En las unidades de endoscopia están todas las formas de contagio: aerosoles (vómitos, arcadas, eructos, flatos), materia fecal, contacto estrecho, contaminación del ambiente. Se deben suspender todas las endoscopias programadas para diagnóstico. Solo deben realizarse las urgentes y terapéuticas. Todo el personal de endoscopia debe tener medidas de protección estrictas. El paciente debe saber que en la sala de endoscopia puede contagiarse, con constancia en el consentimiento informado. Debe contactarse al paciente posendoscopia vía telefónica a los días 7 y 14 para indagar sobre todos los síntomas mencionados.(AU)

SARS-CoV-2 is the coronavirus which produces the dreaded COVID-19. Starting in Wuhan, the capital of China's Hubei province, it has spread it spread throughout the world in less than four months and has caused thousands of deaths. The WHO has declared it to be a pandemic. Humanity is shocked, and many governments have imposed total isolation. It has had varying success due to community negligence. In many cities, institutions and health personnel have not successfully managed this catastrophe. Isolation is the only effective strategy to stop the logarithmic growth of COVID 19. The scientific reason for isolation is that more than 60 % of infections arise from asymptomatic people. SARS-CoV-2 not only produces respiratory symptoms but can also cause nausea, abdominal pain, vomiting, diarrhea, anosmia and ageusia. Fifty percent of those infected may have digestive symptoms which may even precede respiratory symptoms. The fecal-oral route can transmit the virus even when there is no diarrhea. All forms of contagion are found in endoscopy units: aerosols from vomiting, retching, bel-ching, and flatus; fecal matter, close contact, and contamination of the environment. All diagnostic endoscopies should be discontinued. Only urgent and therapeutic endoscopy should be performed. All endoscopy personnel must have strict protection measures. Each patient should be informed, and sign an informed consent form, that the virus can be spread within the endoscopy room. After performance of endoscopy, the patient should be contacted by phone on days 7 and 14 to inquire about all symptoms mentioned.(AU)

Development, Fabrication, and Characterization of Composite Polycaprolactone Membranes Reinforced with TiO2 Nanoparticles.

This paper focuses on developing, fabricating, and characterizing composite polycaprolactone (PCL) membranes reinforced with titanium dioxide nanoparticles (NPs) elaborated by using two solvents; acetic acid and a mixture of chloroform and N,N-dimethylformamide (DMF). The resulting physical, chemical, and mechanical properties of the composite materials are studied by using experimental characterization techniques such as scanning electron microscopy (SEM), differential scanning calorimetry (DSC), X-Ray diffraction (XRD), Fourier-transform infrared (FTIR) analysis, contact angle (CA), uniaxial and biaxial tensile tests, and surface roughness measurements. Experimental results show that the composite material synthesized by sol-gel and chloroform-DMF has a better performance than the one obtained by using acetic acid as a solvent.

Investigation of the Effect of Carbonyl Iron Micro-Particles on the Mechanical and Rheological Properties of Isotropic and Anisotropic MREs: Constitutive Magneto-Mechanical Material Model.

This article focuses on evaluating the influence that the addition of carbonyl iron micro-particles (CIPs) and its alignment have on the mechanical and rheological properties for magnetorheological elastomers (MREs) fabricated using polydimethylsiloxane (PDMS) elastomer, and 24 wt % of silicone oil (SO). A solenoid device was designed and built to fabricate the corresponding composite magnetorheological material and to perform uniaxial cyclic tests under uniform magnetic flux density. Furthermore, a constitutive material model that considers both elastic and magnetic effects was introduced to predict stress-softening and permanent set effects experienced by the MRE samples during cyclic loading tests. Moreover, experimental characterizations via Fourier transform infrared (FTIR), X-ray diffraction (XRD), tensile mechanical testing, and rheological tests were performed on the produced MRE samples in order to assess mechanical and rheological material properties such as mechanical strength, material stiffness, Mullins and permanent set effects, damping ratio, stiffness magnetorheological effect (SMR), and relative magnetorheological storage and loss moduli effects. Experimental results and theoretical predictions confirmed that for a CIPs concentration of 70 wt %, the material samples exhibit the highest shear modulus, stress-softening effects, and engineering stress values when the samples are subject to a maximum stretch value of 1.64 and a uniform magnetic flux density of 52.2 mT.

Políticas públicas y políticas educativas para la primera infancia: desafíos de la formación del educador infantil / Public policies and educational policies for early childhood: Challenges of early childhood educator training / Políticas públicas e políticas educacionais para a primeira infância: desafios da formação de professores na educação infantil

Resumen (analítico): En este artículo se presentan los resultados de una investigación de carácter cualitativo, de tipo descriptivo-interpretativo, la cual correspondió a un análisis documental, cuyo objetivo fue identificar los retos emergentes a la formación del educador infantil que surgen de las políticas educativas nacionales e internacionales. A partir de un análisis de contenido de los textos de política, se exploraron las categorías axiales de políticas públicas, primera infancia y formación docente, ejercicio del que emergieron categorías y subcategorías en relación con los saberes que se esperan de un educador infantil: saberes generales, saberes pedagógicos, saberes didácticos y saberes transversales.

Abstract: The article presents the results of a completed investigation that was implemented using a qualitative descriptive-interpretative approach. This involved the authors conducting a document analysis, which had the purpose of identifying the challenges that emerge in the training of early childhood educators that are the result of national and international educational policies. A content analysis explored the axial categories of public policies: early childhood and teacher training. As a result of the analysis categories and subcategories emerged in the knowledge expected from early childhood teachers: general knowledge, pedagogical knowledge, didactic knowledge and crosscutting knowledge.

Resumo: O artigo apresenta os resultados de uma pesquisa concluída de natureza qualitativa, de tipo descritivo-interpretativo que corresponde a uma análise documental, sua finalidade foi identificar os desafíos emergentes à formação dos pedagogos infantis que surgem desde as políticas educacionais nacionais e internacionais. A partir de uma análise de conteúdo dos textos de política, foram exploradas as categorias axiais de políticas públicas, primeira infância e formação de docentes, exercício do qual emergiram categorias e subcategorias em relação aos saberes que são esperados do educador infantil: saberes gerais, saberes pedagógicos, saberes da didática e saberes transversais.

Fabrication and Characterization of Isotropic and Anisotropic Magnetorheological Elastomers, Based on Silicone Rubber and Carbonyl Iron Microparticles.

This article focuses on studying the rheological behavior of isotropic and anisotropic magnetorheological elastomers (MREs), made of carbonyl iron microparticles dispersed into a silicone⁻rubber matrix by considering 20 and 30 wt % of microparticles. Sample sets were prepared for each composition, with and without the application of an external magnetic field. Experimental measurements of the material rheology behavior were carried out by a shear oscillatory rheometer at constant temperature, to determine both the shear storage modulus (G') and shear loss modulus (G'') for all characterized samples. Then, experimental data collected from the isotropic and the anisotropic material samples were used to plot the Cole-Cole diagrams to quantify the interfacial adhesion between carbonyl iron microparticles and the silicone-rubber matrix. Furthermore, the Fractional Zener Model (FZM) with two spring-pots in series is used for quantitative analysis of collected experimental data.

Improving public transportation systems with self-organization: A headway-based model and regulation of passenger alighting and boarding.

The equal headway instability-the fact that a configuration with regular time intervals between vehicles tends to be volatile-is a common regulation problem in public transportation systems. An unsatisfactory regulation results in low efficiency and possible collapses of the service. Computational simulations have shown that self-organizing methods can regulate the headway adaptively beyond the theoretical optimum. In this work, we develop a computer simulation for metro systems fed with real data from the Mexico City Metro to test the current regulatory method with a novel self-organizing approach. The current model considers overall system's data such as minimum and maximum waiting times at stations, while the self-organizing method regulates the headway in a decentralized manner using local information such as the passenger's inflow and the positions of neighboring trains. The simulation shows that the self-organizing method improves the performance over the current one as it adapts to environmental changes at the timescale they occur. The correlation between the simulation of the current model and empirical observations carried out in the Mexico City Metro provides a base to calculate the expected performance of the self-organizing method in case it is implemented in the real system. We also performed a pilot study at the Balderas station to regulate the alighting and boarding of passengers through guide signs on platforms. The analysis of empirical data shows a delay reduction of the waiting time of trains at stations. Finally, we provide recommendations to improve public transportation systems.

An Optimum Specimen Geometry for Equibiaxial Experimental Tests of Reinforced Magnetorheological Elastomers with Iron Micro- and Nanoparticles.

The aim of this paper focused on obtaining the optimum cruciform geometry of reinforced magnetorheological elastomers (MRE) to perform homogeneous equibiaxial deformation tests, by using optimization algorithms and Finite Element Method (FEM) simulations. To validate the proposed specimen geometry, a digital image correlation (DIC) system was used to compare experimental result measurements with respect to those of FEM simulations. Moreover, and based on the optimum cruciform geometry, specimens produced from MRE reinforced with carbonyl-iron microparticles or iron nanoparticles were subjected to equibiaxial loading and unloading cycles to examine their Mullin's effect and their residual strain deformations.

Experimental Investigation of the Magnetorheological Behavior of PDMS Elastomer Reinforced with Iron Micro/Nanoparticles.

The aim of this article focuses on identifying how the addition of iron micro- and nanoparticles influences the physical properties of magnetorheological composite materials developed with a polydimethylsiloxane (PDMS) matrix with different contents of silicone oil used as additive. A number of characterization techniques have been performed in order to fully characterize the samples, such as cyclic and uniaxial extension, rheology, swelling, Vibrating sample magnetometer (VSM), X-ray Diffraction (XRD), Scanning electron microscopy (SEM), Fourier-Transform Infrared (FTIR), X-ray photoelectronic spectroscopy (XPS) and Thermogravimetric analysis (TGA). The comparison between two matrices with different shore hardnesses and their mechanical and chemical properties are elucidated by swelling and tensile tests. In fact, swelling tests showed that higher crosslink density leads to increasing elongation at break and tensile strength values for the composite materials. The best mechanical performance in the magnetorheological material was observed for those samples manufactured using a higher silicone oil content in a hard polymeric matrix. Furthermore, it has been found that the magnetic properties are enhanced when nanoparticles are used as fillers instead of microparticles.

Guía de práctica clínica para el diagnóstico y tratamiento de la dispepsia en adultos / Clinical Practice Guideline for the diagnosis and treatment of Dyspepsia in adults

Objetivo: con la evidencia más reciente, desarrollar una guía de práctica clínica para el manejo de dispepsia dirigida a pacientes, personal asistencial, administrativo y entes gubernamentales de cualquier servicio de atención en Colombia. Materiales y métodos: esta guía fue desarrollada por un equipo multidisciplinario con el apoyo de la Asociación Colombiana de Gastroenterología, el Grupo Cochrane ITS y el Instituto de Investigaciones Clínicas de la Universidad Nacional de Colombia. Se desarrollaron preguntas clínicas relevantes y se realizó la búsqueda de guías nacionales e internacionales en bases de datos especializadas. Las guías existentes fueron evaluadas en términos de calidad y aplicabilidad; una guía cumplió con el criterio de adaptación, por lo que se adaptaron 2 de sus preguntas. El Grupo Cochrane realizó la búsqueda sistemática de la literatura. Las tablas de evidencia y recomendaciones fueron realizadas con base en la metodología GRADE. Las recomendaciones de la guía fueron socializadas en una reunión de expertos con entes gubernamentales y pacientes. Resultados: se desarrolló una guía de práctica clínica basada en la evidencia para el manejo de pacientes con dispepsia en Colombia. Conclusiones: el tamizaje de pacientes asintomáticos en Colombia, de forma adecuada y con estándares de calidad, tiene el potencial de impactar la carga de cáncer de colon en el país.

Objective: To provide an evidence-based clinical practice guideline for the management of dyspepsia for patients, caregivers, administrative and government bodies at all levels of care in Colombia. Materials and Methods: This guide was developed by a multidisciplinary team with the support of the Colombian Association of Gastroenterology, Cochrane STI Group and Clinical Research Institute of the Universidad Nacional de Colombia. Relevant clinical questions were developed and the search for national and international guidelines in databases was performed. Existing guidelines were evaluated for quality and applicability. One guideline met the criteria for adaptation of two of its clinical questions. Systematic literature searches were conducted by the Cochrane STI Group. The tables of evidence and recommendations were made based on the GRADE methodology. The recommendations of the guide were socialized in a meeting of experts with government agencies and patients. Results: An evidence-based Clinical Practice Guidelines for the management of dyspepsia was developed for the Colombian context. Conclusions: The opportune management of dyspepsia would have an impact of the disease in Colombia.

A novel and highly regioselective synthesis of new carbamoylcarboxylic acids from dianhydrides.

A regioselective synthesis has been developed for the preparation of a series of N,N'-disubstituted 4,4'-carbonylbis(carbamoylbenzoic) acids and N,N'-disubstituted bis(carbamoyl) terephthalic acids by treatment of 3,3',4,4'-benzophenonetetracarboxylic dianhydride (1) and 1,2,4,5-benzenetetracarboxylic dianhydride (2) with arylalkyl primary amines (A-N). The carbamoylcarboxylic acid derivatives were synthesized with good yield and high purity. The specific reaction conditions were established to obtain carbamoyl and carboxylic acid functionalities over the thermodynamically most favored imide group. Products derived from both anhydrides 1 and 2 were isolated as pure regioisomeric compounds under innovative experimental conditions. The chemo- and regioselectivity of products derived from dianhydrides were determined by NMR spectroscopy and confirmed by density functional theory (DFT). All products were characterized by NMR, FTIR, and MS.