l-Amino Acid Production by a Immobilized Double-Racemase Hydantoinase Process: Improvement and Comparison with a Free Protein System

Protein immobilization is proving to be an environmentally friendly strategy for manufacturing biochemicals at high yields and low production costs. This work describes the optimization of the so-called “double-racemase hydantoinase process,” a system of four enzymes used to produce optically pure l-amino acids from a racemic mixture of hydantoins. The four proteins were immobilized separately, and, based on their specific activity, the optimal whole relation was determined. The first enzyme, d,l-hydantoinase, preferably hydrolyzes d-hydantoins from d,l-hydantoins to N-carbamoyl-d-amino acids. The remaining l-hydantoins are racemized by the second enzyme, hydantoin racemase, and continue supplying substrate d-hydantoins to the first enzyme. N-carbamoyl-d-amino acid is racemized in turn to N-carbamoyl-l-amino acid by the third enzyme, carbamoyl racemase. Finally, the N-carbamoyl-l-amino acid is transformed to l-amino acid by the fourth enzyme, l-carbamoylase. Therefore, the product of one enzyme is the substrate of another. Perfect coordination of the four activities is necessary to avoid the accumulation of reaction intermediates and to achieve an adequate rate for commercial purposes. The system has shown a broad pH optimum of 7–9, with a maximum activity at 8 and an optimal temperature of 60 °C. Comparison of the immobilized system with the free protein system showed that the reaction velocity increased for the production of norvaline, norleucine, ABA, and homophenylalanine, while it decreased for l-valine and remained unchanged for l-methionine

Evaluación electroquímica de la estrictosamida como inhibidor de corrosión en la plata sterling 0.925 inmersa en Na₂SO₄ 0.05M

En este estudio se evaluó diferentes concentraciones de un inhibidor de corrosión de origen natural como es la estrictosamida ((3α, 5β, 16β, 17α)- 21-oxo-16-vinil-19,20-dihydro-oxoyoimban-17-il-d-glucopyranoside) sobre la superficie de la plata sterling .925 en una solución de sulfatos. La evaluación electroquímica se realizó utilizando la espectroscopia de impedancia electroquímica (EIS). Los resultados muestran que a 50 ppm es la mejor concentración para proteger a la plata 0.925 en medio de sulfatos. La adsorción del inhibidor se demostró que es una fisisorción-quimisorción de acuerdo a la isoterma de Langmuir, obteniendo un valor de energía libre de adsorción de Gibbs de -37.2 KJ/mol.In this study, different concentrations of a corrosion inhibitor of natural origin such as strictosamide ((3α, 5β, 16β, 17α) -21-oxo-16-vinyl-19,20- dihydro-oxoyoimban-17-il- were evaluated. d-glucopyranoside) on the surface of silver sterling .925 in a chloride solution. The electrochemical evaluation was performed using electrochemical impedance spectroscopy (EIS). The results show that at 50 ppm is the best concentration to protect the 0.925 silver in sulfate medium. The adsorption of the inhibitor was shown to be a physisorption chemisorption according to the Langmuir isotherm, obtaining a Gibbs adsorption-free energy value of -37.2 KJ/mol

Effect of milling time on mechanical properties of fly ash incorporated cement mortars

Abstract. Currently, thermal energy generation through coal combustion produces ash particles which cause serious environmental problems and which are known as Fly Ash (FA). FA main components are oxides of silicon, aluminum, iron, calcium and magnesium in addition, toxic metals such as arsenic and cobalt. The use of fly ash as a cement replacement material increases long term strength and durability of concrete. In this work, samples were prepared by replacing cement by ground fly ash in 10, 20 and 30% by weight. The characterization of raw materials and microstructure was obtained by Scanning Electron Microscopy (SEM) and X-ray diffraction (XRD). The final results showed that the grinding process significantly improves the mechanical properties of all samples when compared replacing a mortar made with cement by ground fly ash and the reference samples without added fly ash. The beneficial effect of the ground fly ash can increase the use of this product in precast concrete industr

Towards a new generation of dynamic indices for the assessment of drug-induced proarrhythmic risk

The detection of proarrhythmic side effects in many marketed drugs has prompted the search for complementary non-invasive markers of cardiotoxicity risk. Novel indices based on the study of cardiac vector dynamics have now emerged. Herein, we use quaternion methods to study alterations in the angular velocity during ventricular repolarization. The assessment was conducted in patients with Torsade de Pointes episodes when undergoing a Sotalol treatment. The algorithm includes a Principal Component Analysis to homogenize the information from three databases and, at the same time, reduce the space to three dimensions. Significant differences were found (p < 5E-4) in the angular velocity of the second half of repolarization loop (T-wave). The ratio between the maximums of the angular velocity in both T-wave halves showed a trend to 1 in the proximity of an arrhythmic event and reached sensitivity/specificity pair of 97/100 (AUC 0.99) in the comparison of healthy population with at-risk patients. The high performance of the method exceeded the expectations of the standard measurement and it becomes a promising outcome for the development of safe drug therapies.Fil: Cruces, Pablo Daniel. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Ingeniería Biomédica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; ArgentinaFil: Alvarado Rodríguez, Francisco Javier. Universidad Autónoma de Guadalajara; MéxicoFil: Romo Vázquez, Rebeca. Universidad de Guadalajara; MéxicoFil: Arini, Pedro David. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Ingeniería Biomédica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; ArgentinaXIX Reunión de trabajo en procesamiento de la información y controlSan JuanArgentinaUniversidad Nacional de San Juan. Instituto de Automátic

Optimización de piezoeléctricos comerciales para su uso en sistemas de Energy Harvesting = Piezoelectric business optimization for use in energy systems harvesting

En este trabajo se caracterizan electromecánicamente materiales piezoeléctricos comerciales individuales y en diferentes configuraciones para su potencial uso en dispositivos detransformación de energía mecánica en eléctrica, con el objetivo de almacenarla y usarla en la alimentación de sistemas electrónicos de bajo consumo. Se plantean modelos optimizados de almacenamiento de dicha energía, teniendo en cuenta 2 posibilidades: captación de energía a partir de vibraciones continuas, incluso de baja intensidad, o captación de energía a partir de impactos. Se estudian diferentes configuraciones y se analiza la viabilidad de los modelos presentados mediante sistemas de vibración de frecuencia controlada y un banco de pruebas de simulación de paso de vehículos, dise˜nado y patentado por el grupo POEMMA R&D. Se enumeran aplicaciones cotidianas en las que pueden usarse los dispositivos en las configuraciones descritas. ABSTRACT. In this work, commercial piezoelectric materials are electromechanically characterized, indifferent configurations for potential use in harvesting devices of mechanical energy, inorder to store and use in the feeding of low power electronic systems. Optimization models considering two different types of mechanical energy are proposed:one for capture energy from continuous vibration, even low intensity and other for capture energy from impacts.Different configurations are discussed, and the feasibility of the models presented is analyzed by frequency vibration systems controlled and a test simulation of passing vehicles, designed and patented by POEMMA R&D group. Everyday applications in which devices in the configurations described may be used are listed

Cinemómetro piezoeléctrico de alta exactitud (VUAE)

Se ha desarrollado un sistema electrónico computerizado, portátil y de bajo consumo, denominado Medidor de Velocidad de Vehículos por Ultrasonidos de Alta Exactitud, VUAE. La alta exactitud de la medida conseguida en el VUAE hace que pueda servir de medida de referencia de la velocidad de un vehículo circulando en carretera. Por tanto el VUAE puede usarse como medida de referencia que permita estimar el error de los cinemómetros comerciales. El VUAE está compuesto por n (n≥2) parejas de emisores y receptores piezoeléctricos de ultrasonidos, denominados E-Rult. Los emisores de las n parejas E-Rult generan n barreras de ultrasonidos, y los receptores piezoeléctricos captan la señal de los ecos cuando el vehículo atraviesa las barreras. Estos ecos se procesan digitalmente para conseguir señales representativas. Posteriormente, utilizando la técnica de la correlación cruzada de señales, se ha podido estimar con alta exactitud la diferencia de tiempos entre los ecos captados en cada barrera. Con los tiempos entre ecos y con la distancia entre cada una de las n barreras de ultrasonidos se puede realizar una estimación de la velocidad del vehículo con alta exactitud. El VUAE se ha contrastado con un sistema de velocidad de referencia, basado en cables piezoeléctricos. ABSTRACT We have developed a portable computerized and low consumption, our system is called High Accuracy Piezoelectric Kinemometer measurement, herein VUAE. By the high accuracy obtained by VUAE it make able to use the VUAE to obtain references measurements of system for measuring Speeds in Vehicles. Therefore VUAE could be used how reference equipment to estimate the error of installed kinemometers. The VUAE was created with n (n≥2) pairs of ultrasonic transmitter-receiver, herein E-Rult. The transmitters used in the n couples E-Rult generate n ultrasonic barriers and receivers receive the echoes when the vehicle crosses the barriers. Digital processing of the echoes signals let us to obtain acceptable signals. Later, by mean of cross correlation technics is possible make a highly exact estimation of speed of the vehicle. The log of the moments of interception and the distance between each of the n ultrasounds allows for a highly exact estimation of speed of the vehicle. VUAE speed measurements were compared to a speed reference system based on piezoelectric cables

Adaptation and psychometric study of the scale for the measurement of fear and anxiety of COVID-19 disease in pregnant women (AMICO_Pregnant)

https://www.frontiersin.org/articles/10.3389/fpubh.2023.1225822/full#supplementary-materialObjective: The aim of this research was to adapt and explore the psychometric properties of a specific scale to assess the levels of fear and anxiety of COVID-19 disease in pregnant women. Methods: An adaptation phase, by a panel of experts, and a psychometric descriptive cross-sectional study were carried out on the final version of the 16- item, self-administered AMICO_Pregnant scale. Univariate and bivariate analyses were carried out, followed by exploratory factor analysis (EFA) and confirmatory factor analysis (CFA). The consistency of the scale was assessed using the Omega coefficient and Cronbach’s Alpha. Results: With a sample of 1,013 pregnant women living in Spain and over 18 years of age, the mean age was 33 years. The scale showed a bifactor structure (anxiety and fear) that was confirmed with good fit parameters. Reliability was assessed in terms of internal consistency by calculating Cronbach’s Alpha coefficient (0.95) and McDonald’s Omega coefficient (0.94) as indicators of robustness of the scale’s reliability. Conclusion: The AMICO_Pregnant scale of 16 items with scores ranging from 1 to 10 is a valid and reliable tool to assess levels of anxiety and fear of COVID_19 in Spanish pregnant women. Pregnant women have shown moderate levels of anxiety and fear regarding the COVID_19 disease in the final phase of the pandemic

Surface expression marker profile in colon cancer cell lines and sphere-derived cells suggests complexity in CD26+ cancer stem cells subsets

Taking advantage of eight established cell lines from colorectal cancer patients at different stages of the disease and the fact that all of them could form spheres, cell surface biomarkers of cancer stem cells and epithelial-mesenchymal transition were tested. The aim was to investigate cancer stem cells and metastatic stem cells in order to provide functional characterization of circulating tumor cells and promote the development of new anti-metastatic therapies. Our model showed an important heterogeneity in EpCAM, CD133, CD44, LGR5, CD26 and E-cadherin expression. We showed the presence of a subset of E-cadherin+ (some cells being E-cadherinhigh) expressing CD26+ (or CD26high) together with the well-known CSC markers LGR5 and EpCAMhigh, sometimes in the absence of CD44 or CD133. The already described CD26+/E-cadherinlow or negative and CD26+/EpCAM−/CD133− subsets were also present. Cell division drastically affected the expression of all markers, in particular E-cadherin, so new-born cells resembled mesenchymal cells in surface staining. CD26 and/or dipeptidyl peptidase 4 inhibitors have already shown anti-metastatic effects in pre-clinical models, and the existence of these CD26+ subsets may help further research against cancer metastasis.This work was done with the Xunta de Galicia grants (supported by the: European Regional Development Fund (ERDF): Axudas consolidación e estructuración de unidades de investigación competitiva [GRC2014/019], Galician Network for Colorectal Cancer Research (REGICC) [R2014/039] and Agrupación estratégica InBiomed [2012/273]S