5,284 research outputs found

    Exploring the Chemistry of the Mechanical Bond: Synthesis of a [2]Rotaxane through Multicomponent Reactions

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    © 2023 The Authors. Published by American Chemical Society and Division of Chemical Education, Inc. This manuscript version is made available under the CC-BY 4.0 license https://creativecommons.org/licenses/by/4.0/ This document is the Published Manuscript version of a Published Work that appeared in final form in Journal of Chemical Education. To access the final edited and published work see https://doi.org/10.1021/acs.jchemed.3c00163The synthesis of a [2]rotaxane through three- or five-component coupling reactions has been adapted to an organic chemistry experiment for upper-division students. The experimental procedure addresses the search for the most favorable reaction conditions for the synthesis of the interlocked compound, which is obtained in a yield of up to 71%. Moreover, the interlocked nature of the rotaxane is proven by NMR spectroscopy. The content of the sessions has been designed on the basis of a proactive methodology whereby upper-division undergraduate students have a dynamic role. The laboratory experience not only introduces students to the chemistry of the mechanical bond but also reinforces their previous knowledge of basic organic laboratory procedures and their skills with structural elucidation techniques such as NMR and FT-IR spectroscopies. The experiment has been designed in such a customizable way that both experimental procedures and laboratory material can be adapted to a wide range of undergraduate course curricula

    Ultrasonic evaluation of different types of mortas subjected to attack by pig slurry

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    This paper presents the mechanical behavior of different types of mortar subjected to attack by real pig slurry. The study of the behaviour of mortars was made by the ultrasonic velocity images, obtained by means of automatic inspection and mechanical test of compressive strength. The use of ultrasonic velocity has allowed the extraction of information on the state of damage to the inspected material. The results obtained from non-destructive ultrasonic tests were compared to destructive testing of compressive strength, and they showed how ultrasonic velocity in the degraded material correlates well with the compressive strength. This conclusion allows us to affirm that the ultrasonic velocity can be used to characterize the process of degradation in cement mortars attacked by pig slurry. The study proposes a mathematic model for estimating compressive strength by measuring variations in ultrasonic velocity

    Privacy Distillation:Reducing Re-identification Risk of Multimodal Diffusion Models

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    Knowledge distillation in neural networks refers to compressing a large model or dataset into a smaller version of itself. We introduce Privacy Distillation, a framework that allows a text-to-image generative model to teach another model without exposing it to identifiable data. Here, we are interested in the privacy issue faced by a data provider who wishes to share their data via a multimodal generative model. A question that immediately arises is ``How can a data provider ensure that the generative model is not leaking identifiable information about a patient?''. Our solution consists of (1) training a first diffusion model on real data (2) generating a synthetic dataset using this model and filtering it to exclude images with a re-identifiability risk (3) training a second diffusion model on the filtered synthetic data only. We showcase that datasets sampled from models trained with privacy distillation can effectively reduce re-identification risk whilst maintaining downstream performance

    Privacy Distillation: Reducing Re-identification Risk of Multimodal Diffusion Models

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    Knowledge distillation in neural networks refers to compressing a large model or dataset into a smaller version of itself. We introduce Privacy Distillation, a framework that allows a text-to-image generative model to teach another model without exposing it to identifiable data. Here, we are interested in the privacy issue faced by a data provider who wishes to share their data via a multimodal generative model. A question that immediately arises is ``How can a data provider ensure that the generative model is not leaking identifiable information about a patient?''. Our solution consists of (1) training a first diffusion model on real data (2) generating a synthetic dataset using this model and filtering it to exclude images with a re-identifiability risk (3) training a second diffusion model on the filtered synthetic data only. We showcase that datasets sampled from models trained with privacy distillation can effectively reduce re-identification risk whilst maintaining downstream performance

    Theoretical Study of Copper Complexes: Molecular Structure, Properties, and Its Application to Solar Cells

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    We present a theoretical investigation of copper complexes with potential applications as sensitizers for solar cells. The density functional theory (DFT) and time-dependent DFT were utilized, using the M06 hybrid meta-GGA functional with the LANL2DZ (D95V on first row) and DZVP basis sets. This level of calculation was used to find the optimized molecular structure, the absorption spectra, the molecular orbitals energies, and the chemical reactivity parameters that arise from conceptual DFT. Solvent effects have been taken into account by an implicit approach, namely, the polarizable continuum model (PCM), using the nonequilibrium version of the IEF-PCM model

    Determinación de los factores de riesgo de la fibrilación auricular y factores predictores de fenómenos cardioembólicos en el Hospital Nacional Sergio E. Bernales - Lima, 2019-2022

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    La fibrilación auricular es la arritmia más trascendental de la práctica médica, su presencia incrementa hasta cinco veces el riesgo de producir un accidente cerebrovascular cardioembólico, cuyas consecuencias merman la calidad de vida. El objetivo del estudio fue determinar la relación que presentan los factores de riesgo modificables como no modificables de la fibrilación auricular con la valoración de riesgo mediante la escala CHA2DS2-VASc y los fenómenos cardioembólicos en el Hospital Nacional Sergio E. Bernales de la ciudad de Lima en el periodo 2019-2022. La investigación fue no experimental, transversal, retrospectiva de alcance correlacional, con una muestra de 197 historias clínicas revisadas. Los resultados señalan que los factores de riesgo no modificables de la fibrilación auricular, tanto la edad como el sexo, percibieron una asociación (p < 0,05) con riesgo cardioembólico alto; respecto a los factores de riesgo modificables de la fibrilación auricular: valvulopatías, enfermedad arterial periférica, sobrepeso, consumo de tabaco y alcohol, presentaron una asociación (p < 0,05) en quienes establecieron una enfermedad cerebrovascular; por otra parte se encontró una asociación (p < 0,05) con los siguientes factores: hipertensión arterial, diabetes mellitus, insuficiencia cardiaca, sobrepeso y tabaco, respecto al riesgo alto de padecer un fenómeno cardioembólico. Las conclusiones señalan que se hallaron factores de riesgo potencialmente modificables como el sobrepeso y tabaco, que están fuera de los factores clásicos descritos en la escala CHA2DS2-VASc. Se recomienda explorar un nuevo enfoque hacia el control de los estilos de vida de manera individual que permitan reducir el desarrollo de enfermedades incapacitantes

    On-line quizzes to evaluate comprehension and integration skills

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    This work demonstrates the use of a 2.0 tool, namely, Socrative, to evaluate one of the cross-curricular competences indicated by the Universitat Politècnica de València, specifically, comprehension and integration. It has been applied to the courses in different areas: sciences, engineering and languages. As part of its implementation, activities were proposed that could be done at the beginning, during or at the end of the class to, on the one hand, help students acquire the knowledge associated with the course(s), and on the other, gather evidence that demonstrates acquisition of said competence. The results show a high level of satisfaction by the students with the use of the Socrative tool as an element to promote active participation and the acquisition of the cross-curricular competence of comprehension and integration; therefore, its extension to other courses has been suggested

    A Novel Noninvasive Approach Based on SPECT and EEG for the Location of the Epileptogenic Zone in Pharmacoresistant Non-Lesional Epilepsy

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    Background and objectives: The aim of this study is to propose a methodology that combines non-invasive functional modalities electroencephalography (EEG) and single photon emission computed tomography (SPECT) to estimate the location of the epileptogenic zone (EZ) for the presurgical evaluation of patients with drug-resistant non-lesional epilepsy. Materials and Methods: This methodology consists of: (i) Estimation of ictal EEG source imaging (ESI); (ii) application of the subtraction of ictal and interictal SPECT co-registered with MRI (SISCOM) methodology; and (iii) estimation of ESI but using the output of the SISCOM as a priori information for the estimation of the sources. The methodology was implemented in a case series as an example of the application of this novel approach for the presurgical evaluation. A gold standard and a coincidence analysis based on measures of sensitivity and specificity were used as a preliminary assessment of the proposed methodology to localize EZ. Results: In patients with good postoperative evolution, the estimated EZ presented a spatial coincidence with the resection site represented by high values of sensitivity and specificity. For the patient with poor postoperative evolution, the methodology showed a partial incoherence between the estimated EZ and the resection site. In cases of multifocal epilepsy, the method proposed spatially extensive epileptogenic zones. Conclusions: The results of the case series provide preliminary evidence of the methodology's potential to epileptogenic zone localization in non-lesion drug-resistant epilepsy. The novelty of the article consists in estimating the sources of ictal EEG using SISCOM result as a prior for the inverse solution. Future studies are necessary in order to validate the described methodology. The results constitute a starting point for further studies in order to support the clinical reliability of the proposed methodology and advocate for their implementation in the presurgical evaluation of patients with intractable non-lesional epilepsy.</p
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