1,862 research outputs found
Continuous conversion of CO2 to alcohols in a TiO2 photoanode-driven photoelectrochemical system
BACKGROUND
The recycling of CO2 by photo-electrochemical reduction has attracted wide interest due to its potential benefits when compared to electro-, and photo-catalysis approaches. Among the different available semiconductors, TiO2 is the most employed material in photo-electrochemical cells. Besides, Cu is a well-known electrocatalyst for alcohols production from CO2 reduction.
RESULTS
In this study, a photo-electrochemical cell consisting on a TiO2 photoanode Membrane Electrode Assembly (MEA) and a Cu plate are employed to reduce CO2 to methanol and ethanol continuously under UV illumination (100 mW·cm-2). A maximum increment of 4.3 mA·cm-2 in current between the illuminated and dark conditions is achieved at -2 V vs. Ag/AgCl. The continuous photo-electrochemical reduction process in the filter-press cell is evaluated in terms of reaction rate (r), as well as Faradaic (FE) and energy (EE) efficiencies. At -1.8 V vs. Ag/AgCl, a maximum reaction rate of r=-9.5 -mol·m-2·s-1, FE=-16.2 % and EE=-5.2 % for methanol, and r=-6.8 -mol·m-2·s-1, FE=-23.2 % and EE=-6.8 % for ethanol can be achieved.
CONCLUSIONS
The potential benefits of the photoanode-driven system, in terms of yields and efficiencies, are observed when employing a TiO2-based MEA photoanode and Cu as dark cathode. The results demonstrate first the effect of UV illumination on current density, and then the formation of alcohols from the continuous photoreduction of CO2. Increasing the external applied voltage led to an enhanced production of methanol, but decreases ethanol formation. The system outperforms previous photoanode-based systems for the CO2-to-alcohols reactions.The authors gratefully acknowledge the financial support from the Spanish Ministry of Economy and Competitiveness (MINECO) through the projects CTQ2016-76231-C2-1-R and Ramón y Cajal programme (RYC-2015-17080)
Determinar tres riesgos operativos o financieros en la decisión de inversión en compra de pagaré de libranzas en empresas comerciales de Bogotá
Trabajo de investigaciónEl presente trabajo pretende determinar tres riesgos operativos o financieros de invertir en compra de pagare libranzas en empresas comerciales de Bogotá. Para desarrollar este trabajo nos basamos en investigaciones ya realizadas en Bogotá por entes de control a empresas operadoras de libranzas, fueron consultadas fuentes primarias como la Procuraduría general de la Nación, Superintendencia de Sociedades, Superintendencia de Industria y Comercio, Superintendencia Financiera, Asobancaria, Superintendencia de la Economía Solidaria con lo referente al tema que nos ocupa.RESUMEN
1. PLANTEAMIENTO DEL PROBLEMA
2. OBJETIVOS
3. JUSTIFICACION
4. METODOLOGIA
5. PLANTEAMIENTO DE HIPOTESIS
6. MARCO REFERENCIA
7. MARCO CONCEPTUAL
8. RESULTADOS DE LA INVESTIGACION
9. CONCLUSIONES
RECOMENDACIONES
BIBLIOGRAFIAEspecializaciónEspecialista en Análisis y Administración Financier
Evaluation of the Impact of a Tourniquet Training Program: A Cross-Sectional Study
Acknowledgments: The company Manzanal Mamphel SA provided the necessary tourniquets for
the pretest and post-test phases of the study (480 devices).Among the main preventable causes of death in the area of operations is external exsanguinating
hemorrhage in the extremities, hence the importance of the tourniquet as a therapeutic
tool in this type of injury and, therefore, of the training of personnel participating in international
missions. The main objective of this study is to determine the impact of training in the application
of this device. This is a quasi-experimental, prospective, cross-sectional study, carried out with
97 healthy volunteers, military personnel who perform their work in the Royal Guard barracks of
El Pardo. The study was conducted between June 2019 and July 2021. The correct determination of
the device placement site and the times of correct device placement were evaluated by determining
whether there was blood flow using Doppler ultrasound measurements. Statistically significant
results were obtained for application time (76.68 s to 58.06 s; p < 0.001), correct device placement
(p < 0.001), and achievement of complete ischemia in the upper extremity (23.7% pretest vs. 24.7%
post-test; p < 0.001). In the lower extremity, after training, longer application duration (43.33 s to
47.30 s) and lower ischemia achievement (59.8% pretest vs. 37.8% post-test) were obtained. Standardized
and regulated training improves device application. More intensive training is necessary to
obtain better results
Estudio espectroscópico e in silico del acoplamiento molecular de clorina e6 con albumina de suero bovino
Con el fin de utilizar especies macrocíclicas tetrapirrólicas en aplicaciones médicas, se investigó la interacción de la albúmina de suero bovino (BSA) con clorina e6 (Ce6), un derivado de clorofila a, a diferentes condiciones de temperatura mediante espectroscopia de fluorescencia y de absorción UV-VIS. Estos resultados se complementaron con estudios in silico de acoplamiento molecular (docking) con el fin de establecer el posible sitio de fijación de Ce6 en BSA. Los resultados de fluorescencia demuestran que el apagamiento estático observado es consecuencia de la formación del complejo BSA-Ce6. El análisis termodinámico indicó que los puentes de hidrógeno y las interacciones de van der Waals son las fuerzas intermoleculares predominantes en el proceso de unión para la estabilización del complejo BSA-Ce6. La simulación in silico del acoplamiento molecular sugiere que el posible sitio de unión de Ce6 se establece en el sitio de unión III de BSA, en la vecindad del residuo de Trp 134.In order to use tetrapyrrolic macrocyclic species in medical applications, the interactions of bovine serum albumin (BSA) with chlorin e6 (Ce6), a chlorophyll a derivative, under different conditions of temperature was investigated by fluorescence and UV-VIS absorption spectroscopies. These results are complemented by in silico molecular docking (docking) studies in order to establish the possible Ce6 binding site on BSA. The binding constants (Kb) values at three different temperatures were calculated using the modified Stern-Volmer equation. The results of fluorescence suggest that the static quenching is the dominant process as a result of the formation of the BSA-Ce6 complex. Thermodynamic analysis shown that hydrogen bonds and van der Waals interactionswere the predominant intermolecular forces in the binding process to stabilize the BSA-Ce6 complex. Molecular docking suggests the probable binding site of the macrocyclic species at BSA occurs in the vicinity of the residue of Trp 134
Optimized manufacturing of gas diffusion electrodes for CO2 electroreduction with automatic spray pyrolysis
Despite being one of the most promising CO2 utilization strategies some aspects still hinder the scaling up of CO2 electroreduction processes. One of them is the fabrication of the electrodes, which is currently rudimentary and depends fundamentally on the human factor. Here, we report an automated spray pyrolysis technique coupled with a plasma surface treatment to fabricate Bi-based gas diffusion electrodes for a enhanced CO2 electroreduction to formate. Three fabrication parameters, namely i) spraying nozzle height, ii) step distance, and iii) ink flow rate, are evaluated to determine the optimal fabrication conditions. The results confirm the reproducibility of the fabrication method, improving the overall performance of the electrodes fabricated with a manual airbrushing method, and leading to formate rates of up to 10.1 mmol m-2 s-1 at 200 mA cm-2. Besides, plasma treatment can improve formate concentration by up to 12 % in comparison with the untreated electrode. As a result, this work provides novel insights into the development of more efficient methods to manufacture electrodes for CO2 electroreduction, which will eventually bring this technology closer to an industrial scale.The authors fully acknowledge the financial support received from the Spanish State Research Agency (AEI) through the projects PID2020-112845RB-I00, TED2021–129810B-C21, PID2019-104050RA-I00, and PLEC2022-009398 (MCIN/AEI/10.13039/501100011033). Jose Antonio Abarca gratefully acknowledges the predoctoral research grant (FPI) PRE2021-097200
Hajdu-Cheney Syndrome: A Novel NOTCH2 Mutation in a Spanish Child in Treatment with Vibrotherapy: A Case Report
A case report of an 11-year-old boy with a de novo variant in NOTCH2 and clinical features
characteristic of Hajdu-Cheney syndrome is reported, with acroosteolysis of the distal phalanges
of the feet and hands, generalized osteoporosis, musculoskeletal and craniofacial alterations, short
stature, bowing of long bones, vertebral anomalies, genu recurvatum, hypertrichosis, joint and
skin hyperlaxity, atopic dermatitis, megalocorneas, micrognathia and frequent respiratory infections,
among others. Treatment is with bisphosphonates in the framework of bone density improvement and
with focal vibration therapy for rehabilitation of the musculoskeletal system and gait improvement.
The three generalities of this pathology—phenotypic variability, degenerative character and the
presence of generalized osteoporosis and acroosteolysis of the distal phalanges—are seen in this case,
whose diagnostic confirmation was made by genetic study
Physical Therapies in the Treatment of Post-COVID Syndrome: A Systematic Review
Introduction: Several days to months after diagnosis of SARS-CoV-2, 35% of patients have
persistent symptoms in high incidence. This is referred to as post-COVID-19 Syndrome. There is
a pressing need to find a way to help patients with the manifested symptoms. Objective: To show
the different therapies that exist for post-COVID Syndrome and their efficacy. Methodology: A
systematic review of the scientific literature was carried out. The data search was carried out in
Scopus, PubMed, Cinahl, andWeb of Science. Of the 106 articles found, 12 articles were obtained after
applying the following eligibility criteria. Results: Interventions related to respiratory musculature
and moderate intensity exercise both in supervised face-to-face sessions and in supervised home
sessions led patients to a significant improvement in the symptoms presented. Conclusion: Physical
therapies significantly reduce fatigue and dyspnea as well as other symptoms related to quality of lif
Procedimiento para la Aplicación de Sanciones en el Régimen Disciplinario Penitenciario de la Ley Penitenciaria y su Reglamento Vigente.
Reseña Histórica del Régimen Disciplinario Penitenciario en El Salvador – El Derecho Disciplinario Penitenciario – Procedimiento para la aplicación de sanciones en el Régimen Disciplinario penitenciario de la Ley Penitenciaria y su Reglamento – Derecho Comparado sobre el procedimiento para la aplicación de sanciones en el Régimen Disciplinario Penitenciario
COVID-19 in Pregnant Women, Maternal—Fetal Involvement, and Vertical Mother-to-Child Transmission: A Systematic Review
Pregnant women are included in the COVID-19 risk groups even if they do not have any
pathology. This requires an analysis of research focused on pregnant women to understand the
impact of SARS-CoV-2 on their condition. There is also a need to know whether there is vertical
mother-to-child transmission, as well as other consequences in case the pregnant woman is infected
and COVID-19 positive. A systematic review was carried out to analyze the existing information on
the complications of a pregnant woman infected with the SARS-CoV-2 coronavirus and the possibility
of vertical transmission from mother to child, registered in the PROSPERO website and searched in
the PubMed, Scopus, CINAHL, and Cochrane Library databases. Finally, 22 articles were included in
the review. The review suggests that vertical transmission from mother to child could be exceptionally
possible at the time of delivery or breastfeeding, but not through the placenta. It is interesting to
point out the good acceptance of vaccination by pregnant women, which may be the reason for the
low infectivity. Further research on pregnant women should be carried out to provide evidence on
vertical mother-to-child transmission and the role of breast milk in relation to SARS-CoV-2
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