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1.
J Cardiovasc Dev Dis ; 11(4)2024 Apr 19.
Artículo en Inglés | MEDLINE | ID: mdl-38667742

RESUMEN

Pulmonary hypertension (PH) can arise from several distinct disease processes, with a percentage presenting with combined pre- and postcapillary pulmonary hypertension (cpcPH). Patients with cpcPH are unsuitable candidates for PH-directed therapies due to elevated pulmonary capillary wedge pressures (PCWPs); however, the PCWP is dynamic and is affected by both preload and afterload. Many patients that are diagnosed with cpcPH are hypertensive at the time of right heart catheterization which has the potential to increase the PCWP and, therefore, mimic a more postcapillary-predominant phenotype. In this small pilot study, we examine the effect of nitroprusside combined with dynamic preload augmentation with a passive leg raise maneuver in hypertensive cpcPH patients at the time of right heart catheterization to identify a more precapillary-dominant PH phenotype. Patients that met the criteria of PCWP ≤ 15 mmHg with nitroprusside infusion and PCWP ≤ 18 mmHg with nitroprusside infusion and simultaneous leg raise were started on pulmonary vascular-targeted therapy. Long-term PH therapy was well tolerated, with increased six-minute walk distance, improved WHO functional class, decreased NT-proBNP, and improved REVEAL 2.0 Lite Risk Score in this precapillary-dominant PH phenotype. This small study highlights the importance of characterizing patient physiology beyond resting conditions at the time of right heart catheterization.

2.
Molecules ; 28(19)2023 Sep 23.
Artículo en Inglés | MEDLINE | ID: mdl-37836621

RESUMEN

A theoretical analysis of the potential inhibition of human sucrase-isomaltase (SI) by flavonoids was carried out with the aim of identifying potential candidates for an alternative treatment of type 2 diabetes. Two compounds from maize silks, maysin and luteolin, were selected to be studied with the structure-based density functional theory (DFT), molecular docking (MDock), and molecular dynamics (MD) approaches. The docking score and MD simulations suggested that the compounds maysin and luteolin presented higher binding affinities in N-terminal sucrase-isomaltase (NtSI) than in C-terminal sucrase-isomaltase (CtSI). The reactivity parameters, such as chemical hardness (η) and chemical potential (µ), of the ligands, as well as of the active site amino acids of the NtSI, were calculated by the meta-GGA M06 functional in combination with the 6-31G(d) basis set. The lower value of chemical hardness calculated for the maysin molecule indicated that this might interact more easily with the active site of NtSI, in comparison with the values of the acarbose and luteolin structures. Additionally, a possible oxidative process was proposed through the quantum chemical calculations of the electronic charge transfer values (∆N) between the active site amino acids of the NtSI and the ligands. In addition, maysin displayed a higher ability to generate more oxidative damage in the NtSI active site. Our results suggest that maysin and luteolin can be used to develop novel α-glucosidase inhibitors via NtSI inhibition.


Asunto(s)
Diabetes Mellitus Tipo 2 , Humanos , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Zea mays/metabolismo , Simulación del Acoplamiento Molecular , Luteolina/farmacología , Oligo-1,6-Glucosidasa/química , Sacarasa/metabolismo , Fitoquímicos/farmacología , Fitoquímicos/uso terapéutico , Aminoácidos
3.
Psychiatry Res ; 328: 115428, 2023 10.
Artículo en Inglés | MEDLINE | ID: mdl-37643532

RESUMEN

Students in healthcare careers present stigma towards people with psychiatric diagnoses, so the development of interventions to reduce it is essential. This study aimed to evaluate the effectiveness of an intervention to reduce stigma towards people diagnosed with mental disorders in healthcare students in Chile. A randomized clinical trial with a before and after measurement was carried out. The intervention was part of a compulsory course and combined educational and contact strategies. A total of 244 fourth-semester students of medicine, nursing, dentistry, obstetrics, psychology, and social work participated. The intervention was effective in reducing stigmatizing attitudes and the desire for social distance. For almost all variables, the magnitude of the stigma reduction depended on the initial level of stigma, not on the profession. The intervention had positive effects on all careers. In conclusion, incorporating a stigma reduction intervention into mandatory professional training, with the active participation of the teacher in charge and experts by experience, can be a valuable tool to promote humanized and non-stigmatizing treatment.


Asunto(s)
Trastornos Mentales , Estudiantes de Medicina , Humanos , Universidades , Actitud del Personal de Salud , Estigma Social , Trastornos Mentales/diagnóstico , Trastornos Mentales/terapia , Trastornos Mentales/psicología , Estudiantes de Medicina/psicología
5.
New Microbes New Infect ; 53: 101154, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-37260588

RESUMEN

Background: Mpox is a rare zoonotic disease caused by the Mpox virus. On May 21, 2022, WHO announced the emergence of confirmed Mpox cases in countries outside the endemic areas in Central and West Africa. Methods: This multicentre study was performed through the Infectious Diseases International Research Initiative network. Nineteen collaborating centres in 16 countries participated in the study. Consecutive cases with positive Mpoxv-DNA results by the polymerase chain reaction test were included in the study. Results: The mean age of 647 patients included in the study was 34.5.98.6% of cases were males, 95.3% were homosexual-bisexual, and 92.2% had a history of sexual contact. History of smallpox vaccination was present in 3.4% of cases. The median incubation period was 7.0 days. The most common symptoms and signs were rashes in 99.5%, lymphadenopathy in 65.1%, and fever in 54.9%. HIV infection was present in 93.8% of cases, and 17.8% were followed up in the hospital for further treatment. In the two weeks before the rash, prodromal symptoms occurred in 52.8% of cases. The incubation period was 3.5 days shorter in HIV-infected Mpox cases with CD4 count <200/µL, we disclosed the presence of lymphadenopathy, a characteristic finding for Mpox, accompanied the disease to a lesser extent in cases with smallpox vaccination. Conclusions: Mpox disseminates globally, not just in the endemic areas. Knowledge of clinical features, disease transmission kinetics, and rapid and effective implementation of public health measures are paramount, as reflected by our findings in this study.

8.
Bol Med Hosp Infant Mex ; 79(4): 237-247, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36100208

RESUMEN

BACKGROUND: Respiratory distress syndrome (RDS) is Mexico's second leading cause of neonatal mortality. The 75% reduction in mortality due to RDS has been attributed to the use of nasal continuous positive airway pressure (nCPAP). A survey was conducted to determine the perception of the medical staff regarding the availability of nCPAP equipment and supplies in Mexican hospitals with neonatal intensive care units (NICUs). METHODS: We sent a survey via e-mail to several neonatologists in each state of the country, requesting only one response per hospital. We performed statistical analysis with SPSS software. RESULTS: We received 195 surveys from private (HPri) and public (HPub) hospitals with NICUs nationwide: 100% of HPri and 39% of HPub. More than 75% of the nursing and medical staff had received formal training in nCPAP in 11% of HPri and 5% of HPub. The perceived availability of CPAP equipment was 83.7% vs. 52.1%; nasal cannula supply, 75.5% vs. 36.3%; air/oxygen blender availability, 51.0% vs. 32.9%, in HPri and HPub, respectively. The observed differences were statistically significant. Significant differences were also found among healthcare institutions. CONCLUSIONS: The availability of CPAP equipment and consumables between HPub and HPri is unbalanced and is lower in public institutions. Bubble CPAP is not included essential equipment in the national catalog of instruments and equipment for public hospitals, and its request is complicated. The training of CPAP staff and the availability of bubble CPAP and supplies in public hospitals should be improved.


INTRODUCCIÓN: El síndrome de dificultad respiratoria (SDR) es la segunda causa de mortalidad neonatal en México. La reducción del 75% de la mortalidad por SDR se le ha atribuido al uso de la presión positiva nasal continua de las vías respiratorias (nCPAP). Se realizó una encuesta con el objetivo de conocer la percepción del personal médico acerca de la disponibilidad del equipo e insumos para nCPAP en hospitales de México que cuenten con unidades de cuidados intensivos neonatales (UCIN). MÉTODOS: La encuesta se envió por correo electrónico a varios neonatólogos de cada estado del país y se solicitó una sola respuesta por cada hospital. El análisis estadístico se realizó con el software SPSS. RESULTADOS: Se recibieron 195 encuestas respondidas tanto de hospitales privados (HPri) como públicos (HPub) que cuentan con UCIN a escala nacional: el 100% de HPri y el 39% de HPub. Más del 75% del personal de enfermería y médico recibió una capacitación formal en nCPAP en el 11% de HPri y el 5% de HPub. La percepción de disponibilidad de equipos de presión positiva continua de las vías respiratorias (CPAP) fue del 83.7% vs. el 52.1%; el abasto de cánulas nasales, del 75.5% vs. el 36.3%; la disponibilidad del mezclador aire/oxígeno, del 51.0 % vs. el 32.9%, en HPri y HPub, respectivamente. Las diferencias fueron estadísticamente significativas. También se encontraron diferencias significativas entre las instituciones de salud. CONCLUSIONES: La disponibilidad de equipo y material de consumo para CPAP entre HPub y HPri es desequilibrada, y es menor en las instituciones públicas. El CPAP burbuja no se encuentra incluido en el cuadro básico de equipo médico y se dificulta su solicitud. Debe mejorarse la capacitación del personal en CPAP y la disponibilidad de CPAP burbuja e insumos en los hospitales públicos.


Asunto(s)
Neonatología , Síndrome de Dificultad Respiratoria del Recién Nacido , Presión de las Vías Aéreas Positiva Contínua , Humanos , Recién Nacido , Unidades de Cuidado Intensivo Neonatal , Percepción
9.
Postepy Dermatol Alergol ; 39(3): 517-523, 2022 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-35950121

RESUMEN

Introduction: There is increasing evidence that immunohistochemical expression of p53, Ki-67, and Bcl-2 is associated with aggressive (aBCC) and less aggressive (nBCC) histological subtypes and may have a prognostic role. Aim: To investigate the clinicopathological features and immunohistochemical expressions of p53, Ki-67, and Bcl-2 in cutaneous basal cell carcinoma focusing on histological subtypes. Their roles and possible interactions in the development and progression of BCC are discussed. Material and methods: A total of 50 BCC samples from 50 patients from Western Mexico between June 2018 and June 2019 were included. Paraffin-embedded samples were immunostained with p53, Ki-67, and Bcl-2 antibodies. Semi-quantitative analysis was performed to determine the intensity and positivity of immunostained cells. Parametrical and non-parametrical tests were performed according to the sample's distribution. Results: Samples included 21 nBCC and 29 aBCC. The statistical analysis showed statistical association when grouped as non-aggressive and aggressive subtypes for p53 (p = 0.04) and Bcl-2 (p < 0.01). An inverse negative correlation was found between age and Bcl-2 expression. No statistical association was found between Ki-67 immunoreactivity and any of the other variables. Conclusions: We found that a high expression of Bcl-2 and a low expression of p53 was associated with more indolent histopathological features of BCC and therefore better outcomes. These findings suggest that examination of p53 and Bcl-2 expression in BCC patients may provide valuable prognostic information. These biomarkers may play a role in the development and progression of some cases of BCC.

10.
Bol. méd. Hosp. Infant. Méx ; 79(4): 237-247, Jul.-Aug. 2022. tab, graf
Artículo en Inglés | LILACS-Express | LILACS | ID: biblio-1403645

RESUMEN

Abstract Background: Respiratory distress syndrome (RDS) is Mexico's second leading cause of neonatal mortality. The 75% reduction in mortality due to RDS has been attributed to the use of nasal continuous positive airway pressure (nCPAP). A survey was conducted to determine the perception of the medical staff regarding the availability of nCPAP equipment and supplies in Mexican hospitals with neonatal intensive care units (NICUs). Methods: We sent a survey via e-mail to several neonatologists in each state of the country, requesting only one response per hospital. We performed statistical analysis with SPSS software. Results: We received 195 surveys from private (HPri) and public (HPub) hospitals with NICUs nationwide: 100% of HPri and 39% of HPub. More than 75% of the nursing and medical staff had received formal training in nCPAP in 11% of HPri and 5% of HPub. The perceived availability of CPAP equipment was 83.7% vs. 52.1%; nasal cannula supply, 75.5% vs. 36.3%; air/oxygen blender availability, 51.0% vs. 32.9%, in HPri and HPub, respectively. The observed differences were statistically significant. Significant differences were also found among healthcare institutions. Conclusions: The availability of CPAP equipment and consumables between HPub and HPri is unbalanced and is lower in public institutions. Bubble CPAP is not included essential equipment in the national catalog of instruments and equipment for public hospitals, and its request is complicated. The training of CPAP staff and the availability of bubble CPAP and supplies in public hospitals should be improved.


Resumen Introducción: El síndrome de dificultad respiratoria (SDR) es la segunda causa de mortalidad neonatal en México. La reducción del 75% de la mortalidad por SDR se le ha atribuido al uso de la presión positiva nasal continua de las vías respiratorias (nCPAP). Se realizó una encuesta con el objetivo de conocer la percepción del personal médico acerca de la disponibilidad del equipo e insumos para nCPAP en hospitales de México que cuenten con unidades de cuidados intensivos neonatales (UCIN). Métodos: La encuesta se envió por correo electrónico a varios neonatólogos de cada estado del país y se solicitó una sola respuesta por cada hospital. El análisis estadístico se realizó con el software SPSS. Resultados: Se recibieron 195 encuestas respondidas tanto de hospitales privados (HPri) como públicos (HPub) que cuentan con UCIN a escala nacional: el 100% de HPri y el 39% de HPub. Más del 75% del personal de enfermería y médico recibió una capacitación formal en nCPAP en el 11% de HPri y el 5% de HPub. La percepción de disponibilidad de equipos de presión positiva continua de las vías respiratorias (CPAP) fue del 83.7% vs. el 52.1%; el abasto de cánulas nasales, del 75.5% vs. el 36.3%; la disponibilidad del mezclador aire/oxígeno, del 51.0 % vs. el 32.9%, en HPri y HPub, respectivamente. Las diferencias fueron estadísticamente significativas. También se encontraron diferencias significativas entre las instituciones de salud. Conclusiones: La disponibilidad de equipo y material de consumo para CPAP entre HPub y HPri es desequilibrada, y es menor en las instituciones públicas. El CPAP burbuja no se encuentra incluido en el cuadro básico de equipo médico y se dificulta su solicitud. Debe mejorarse la capacitación del personal en CPAP y la disponibilidad de CPAP burbuja e insumos en los hospitales públicos.

12.
Bol Med Hosp Infant Mex ; 78(1): 34-40, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33661873

RESUMEN

Background: On March 11, 2020, the World Health Organization declared the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) pandemic, and on February 28, Mexico reported its first case. Internationally, cases in newborns are few and the outcomes, in general, are good. There is no certainty of possible vertical transmission, and the presence of the virus in human milk is improbable. The gold standard for diagnosis is the reverse transcription-polymerase chain reaction (RT-PCR) test. We performed a literature review and presented a case of perinatal COVID-19. Clinical case: We describe the case of a full-term male infant with a birth weight of 3450 g and history of rooming-in with another mother-baby pair, both positive for SARS-CoV-2. On the second day of life, the neonate developed pneumonia, with clinical, X-ray and ultrasound diagnostic confirmation. On the third day of life, RT-PCR was positive for SARS-CoV-2; the mother was also positive but remained asymptomatic. The patient required mechanical ventilation and was transferred to a tertiary level neonatal unit on day 5 of life, where congenital heart disease was ruled out. He evolved satisfactorily with a negative RT-PCR test for SARS-CoV-2 on day 8 and was extubated and discharged on day 21 of life. Telephone follow-up was performed without complications. Conclusions: The present case was classified as horizontal transmission with a short incubation period of COVID-19.


Introducción: El 11 de marzo de 2020 la Organización Mundial de la Salud declaró la pandemia por SARS-CoV-2 y el 28 de febrero México reportó su primer caso. En todo el mundo, los casos en recién nacidos son pocos y la evolución, en general, es buena. No hay certeza sobre la posible transmisión vertical, y la presencia del virus en la leche humana es altamente improbable. El método de referencia para el diagnóstico es la prueba de reacción en cadena de la polimerasa con transcriptasa inversa (RT-PCR). Se presenta un caso clínico de COVID-19 perinatal y se llevó a cabo una revisión de la literatura sobre el tema. Caso clínico: Recién nacido de sexo masculino, de término, con un peso al nacer de 3,450 g, con antecedente de alojamiento conjunto con otro binomio madre-hijo positivo para SARS-CoV-2. Al segundo día de vida desarrolló neumonía diagnosticada por clínica, rayos X y ultrasonido. Presentó prueba positiva para SARS-CoV-2 al día 3 de vida, al igual que la madre, quien permaneció asintomática. El paciente requirió ventilación mecánica y fue trasladado a una unidad neonatal de tercer nivel el día 5 de vida, donde se descartó cardiopatía congénita y evolucionó satisfactoriamente. La prueba de RT-PCR para SARS-CoV-2 fue negativa al día 8, por lo que se realizó extubación y egreso al día 21 de vida. Se realizó seguimiento telefónico, sin complicaciones. Conclusiones: El presente caso fue catalogado como transmisión horizontal con un periodo corto de incubación de COVID-19.


Asunto(s)
COVID-19/transmisión , Transmisión Vertical de Enfermedad Infecciosa , Complicaciones Infecciosas del Embarazo/virología , COVID-19/diagnóstico , Prueba de COVID-19 , Femenino , Estudios de Seguimiento , Humanos , Lactante , Recién Nacido , Masculino , México , Embarazo , Complicaciones Infecciosas del Embarazo/diagnóstico , Respiración Artificial , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Adulto Joven
13.
Bol. méd. Hosp. Infant. Méx ; 78(1): 34-40, Jan.-Feb. 2021. graf
Artículo en Inglés | LILACS | ID: biblio-1153237

RESUMEN

Abstract Background: On March 11, 2020, the World Health Organization declared the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) pandemic, and on February 28, Mexico reported its first case. Internationally, cases in newborns are few and the outcomes, in general, are good. There is no certainty of possible vertical transmission, and the presence of the virus in human milk is improbable. The gold standard for diagnosis is the reverse transcription-polymerase chain reaction (RT-PCR) test. We performed a literature review and presented a case of perinatal COVID-19. Clinical case: We describe the case of a full-term male infant with a birth weight of 3450 g and history of rooming-in with another mother-baby pair, both positive for SARS-CoV-2. On the second day of life, the neonate developed pneumonia, with clinical, X-ray and ultrasound diagnostic confirmation. On the third day of life, RT-PCR was positive for SARS-CoV-2; the mother was also positive but remained asymptomatic. The patient required mechanical ventilation and was transferred to a tertiary level neonatal unit on day 5 of life, where congenital heart disease was ruled out. He evolved satisfactorily with a negative RT-PCR test for SARS-CoV-2 on day 8 and was extubated and discharged on day 21 of life. Telephone follow-up was performed without complications. Conclusions: The present case was classified as horizontal transmission with a short incubation period of COVID-19.


Resumen Introducción: El 11 de marzo de 2020 la Organización Mundial de la Salud declaró la pandemia por SARS-CoV-2 y el 28 de febrero México reportó su primer caso. En todo el mundo, los casos en recién nacidos son pocos y la evolución, en general, es buena. No hay certeza sobre la posible transmisión vertical, y la presencia del virus en la leche humana es altamente improbable. El método de referencia para el diagnóstico es la prueba de reacción en cadena de la polimerasa con transcriptasa inversa (RT-PCR). Se presenta un caso clínico de COVID-19 perinatal y se llevó a cabo una revisión de la literatura sobre el tema. Caso clínico: Recién nacido de sexo masculino, de término, con un peso al nacer de 3,450 g, con antecedente de alojamiento conjunto con otro binomio madre-hijo positivo para SARS-CoV-2. Al segundo día de vida desarrolló neumonía diagnosticada por clínica, rayos X y ultrasonido. Presentó prueba positiva para SARS-CoV-2 al día 3 de vida, al igual que la madre, quien permaneció asintomática. El paciente requirió ventilación mecánica y fue trasladado a una unidad neonatal de tercer nivel el día 5 de vida, donde se descartó cardiopatía congénita y evolucionó satisfactoriamente. La prueba de RT-PCR para SARS-CoV-2 fue negativa al día 8, por lo que se realizó extubación y egreso al día 21 de vida. Se realizó seguimiento telefónico, sin complicaciones. Conclusiones: El presente caso fue catalogado como transmisión horizontal con un periodo corto de incubación de COVID-19.


Asunto(s)
Femenino , Humanos , Lactante , Recién Nacido , Masculino , Embarazo , Adulto Joven , Complicaciones Infecciosas del Embarazo/virología , Transmisión Vertical de Enfermedad Infecciosa , COVID-19/transmisión , Complicaciones Infecciosas del Embarazo/diagnóstico , Respiración Artificial , Estudios de Seguimiento , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Prueba de COVID-19 , COVID-19/diagnóstico , México
14.
RSC Adv ; 11(11): 6221-6233, 2021 Feb 02.
Artículo en Inglés | MEDLINE | ID: mdl-35423152

RESUMEN

Ruthenium-silica hybrid material (RuCl2(PR3)2-2-PyCH-AMPTSi/SiO2) was prepared and characterized by various spectroscopic techniques. A deconvolution procedure was applied to the spectroscopic data to deconstruct the overlapped bands. A density functional theoretical approach was applied to get insights into the electronic structure of the ruthenium coordination site and the functional RI-PBE-D3/Def2TZVP basis set was used for the optimization. Relativistic effects were considered using the zero-order regular approximation (ZORA). The anchoring process, evinced for each step of the synthesis of the hybrid material, was tracked by FT-IR analyses. The transitions observed in the FT-IR spectra were verified by DFT analyses, which agree with the experimental data. In the DRS-UV-Vis spectra, three main bands were detected by the deconvolution procedure that correspond to the charge transfer transitions, with the main contributions from ruthenium-chlorine and imine-pyridine fragments. TD-DFT results reveal that ruthenium-chlorine antibonding orbitals act as main charge donors, while pyridine-imine is the main charge acceptor.

15.
J Clin Pediatr Dent ; 44(4): 221-227, 2020 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-33167023

RESUMEN

Dental treatment for anxious or fearful intellectually disabled children/adolescents (IDCA) may present great challenges, due to deficits in cognitive, intellectual, language, and social abilities, in conjunction with limited adaptive behavior. In many cases, it is necessary for the Dentist to implement advanced behavioral control techniques. Inclusive Dentistry (ID) considers profoundly each patient's individual interests and likes, including the social and family situations, for choosing the respective personalized plan -contemplating potential risks and benefits- for the behavior control, in order to obtain the maximal possible cooperation of the patient in the dental chair. Through ID, the Pediatric Dental Practitioner aims to alleviate the anxiety and fear of IDCA in the clinical setting, in such a way that these patients are positively motivated, on a long-term basis, for current and future oral care, both at the dental office and at home. This management approach may be a time-consuming method or require more effort by the dentist, but it reaps benefits when applied for many mild-to-moderate (and some severe) IDCA. The Practitioner must possess the knowledge, in-depth understanding, and professional training for the adequate use of ID during the behavioral management of anxious or fearful IDCA. The aim of the present report was to describe four representative clinical cases of IDCA at our Clinic, managed under the philosophical principles of ID.


Asunto(s)
Discapacidad Intelectual , Adolescente , Niño , Odontología , Odontólogos , Miedo , Humanos , Discapacidad Intelectual/terapia , Odontología Pediátrica , Rol Profesional
16.
ACS Appl Mater Interfaces ; 12(35): 39074-39081, 2020 Sep 02.
Artículo en Inglés | MEDLINE | ID: mdl-32805928

RESUMEN

Catalytic systems whose properties can be systematically tuned via changes in synthesis conditions are highly desirable for the next-generation catalyst design and optimization. Herein, we present a two-dimensional (2D) conductive metal-organic framework consisting of M-N4 units (M = Ni, Cu) and a hexaaminobenzene (HAB) linker as a catalyst for the oxygen reduction reaction. By varying synthetic conditions, we prepared two Ni-HAB catalysts with different crystallinities, resulting in catalytic systems with different electric conductivities, electrochemical activity, and stability. We show that crystallinity has a positive impact on conductivity and demonstrate that this improved crystallinity/conductivity improves the catalytic performance of our model system. Additionally, density functional theory simulations were performed to probe the origin of M-HAB's catalytic activity, and they suggest that M-HAB's organic linker acts as the active site with the role of the metal being to modulate the linker sites' binding strength.

17.
J Phys Chem B ; 124(16): 3355-3370, 2020 04 23.
Artículo en Inglés | MEDLINE | ID: mdl-32216349

RESUMEN

The Gibbs free energy of complexation between the Zn(II) species and acetate ligands, forming the [Zn(OAc)n]2-n complexes with n = 1, 2 in an ethanol solution, was assessed by two different theoretical protocols based on thermodynamic cycles. In both approaches, the solution phase Gibbs free energy of each reaction is computed by summing up contributions from gas phase thermochemistry calculations to solvation Gibbs free energies obtained in a hybrid fashion, i.e., each (neutral or electrically charged) solute was first solvated by explicit solvent molecules in order to capture relevant (micro) solute-solvent and/or solvent-solvent interactions and then, a continuum model calculation is performed in order to get the corresponding bulky solute-solvent contributions. For our first thermodynamic protocol, here denominated as variant 1, a set of x independent solvent molecules are used to screen each of the involved solutes, while the variant 2 strategy uses the fact that a set of solvent molecules may exist as aggregates (or molecular clusters) in the solvent macroscopic media, before the solvation process of solutes. Our selected quantum theoretical protocol was the M05-2X/6-31+G(d)/SMD level. We made a systematic exploration about the influence of several sources of errors, such as the solvent conformation, the number of solvent molecules used to screen each of the involved solutes, the coordination geometry of the metallic center before and after the complexation process, and the pertinence of using molecular geometries optimized in gas phase and in ethanol solution, for the computation of the Gibbs free energy variation regarding the two chemical reactions under study. We set an accuracy threshold equal or less than 4.0 kcal·mol-1, with respect to the corresponding experimental records. The robustness of our thermodynamic strategies was then tested by computing the gas phase free energy contributions to the (solution phase) reaction free energies here assessed, using different density functional approximations, namely the M05-2X, BH&HLYP, PBE0, ωb97X-D and M06-2X functionals in conjunction with the larger 6-311+G(d,p) basis set.


Asunto(s)
Etanol , Acetato de Zinc , Soluciones , Solventes , Termodinámica
18.
Phys Chem Chem Phys ; 22(10): 5969-5975, 2020 Mar 11.
Artículo en Inglés | MEDLINE | ID: mdl-32123887

RESUMEN

Many breakthroughs have been achieved in rechargeable aluminum-ion battery technologies in recent years. Most recently, operando X-ray diffraction (XRD) combined with density functional theory (DFT) calculations was reported to study the chloroaluminate anion (AlCl4-)-intercalated graphite cathode of the battery. However, there are quite a few discrepancies between the measured and simulated XRD patterns. This work is focused on the simulation of XRD patterns of graphite intercalation compounds (GICs) with DFT calculations. Our results reveal that both the geometry of AlCl4- in graphite and the gallery height of GICs are dependent on the intercalant density. At low intercalant density, the gallery height keeps constant, but at high intercalant densities, the gallery height is linearly related to the intercalant density. Our simulated XRD patterns are highly consistent with the measured operando XRD patterns. Not only do the angles of the peaks match very well, but also the relative intensities and the corresponding electrode capacities show reasonable agreement with the experimental results. The DFT simulation of the XRD pattern provides significant information on the stage index and the charge capacity of the GIC electrode.

19.
Chem Sci ; 11(32): 8517-8532, 2020 Jul 30.
Artículo en Inglés | MEDLINE | ID: mdl-34123112

RESUMEN

We present an end-to-end computational system for autonomous materials discovery. The system aims for cost-effective optimization in large, high-dimensional search spaces of materials by adopting a sequential, agent-based approach to deciding which experiments to carry out. In choosing next experiments, agents can make use of past knowledge, surrogate models, logic, thermodynamic or other physical constructs, heuristic rules, and different exploration-exploitation strategies. We show a series of examples for (i) how the discovery campaigns for finding materials satisfying a relative stability objective can be simulated to design new agents, and (ii) how those agents can be deployed in real discovery campaigns to control experiments run externally, such as the cloud-based density functional theory simulations in this work. In a sample set of 16 campaigns covering a range of binary and ternary chemistries including metal oxides, phosphides, sulfides and alloys, this autonomous platform found 383 new stable or nearly stable materials with no intervention by the researchers.

20.
Dermatol Reports ; 12(3): 8836, 2020 Dec 22.
Artículo en Inglés | MEDLINE | ID: mdl-33408842

RESUMEN

Eruptive pseudoangiomatosis is a cutaneous disease of unknown origin, characterized by the sudden appearance of small, asymptomatic angioma-like erythematous papules surrounded by a pale halo that resolves spontaneously. It occurs due to transitory dermal blood vessel dilation and has been associated with viral infections and hematologic disorders. To this day, it remains a disease that affects mostly the lower spectrum of life. Most of the cases have been reported in children and few reports have described its association with immune system disorders. The diagnosis is based upon clinical presentation. Histopathological analysis has no pathognomonic findings and can include dilated dermal blood vessels, perivascular lymphocytic infiltration and plump endothelial cells. We report a 21-years-old female diagnosed with HIV in AIDS stage and a 19- years-old male diagnosed with non- Hodgkin's lymphoma.

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