Screw reactor design for potato peel pretreatment using the steam explosion.

In this article we can observe the scanning by the literature for the pretreatment of steam explosion applied to lignocellulose biomass. A comparison of the chemical and physical characterization of potato peel as a lignocellulose biomass. Besides, the innovative design of a continuous reactor for the potato peel steam explosion process is shown, with specific temperature and pressure conditions on a pilot scale, detailing its parts. Finally, a finite element analysis was performed where stress results were obtained from the reactor material, severity factor, structural analysis and thermal analysis, providing a panorama of the reactor's behavior with the conditions specific.

Graphene oxide obtention via liquid phase exfoliation from high-rank coal: A comparison of mineral matter removal by alkaline bath.

Colombia is one of the world's leading exporters of coal and coke, with significant reserves of high-quality coal. Most of the coal exported from Colombia is used for power generation, but there is also a class of coal that is suitable for making coke. Coke is a raw material required for making steel, and it is produced by heating coal to high temperatures in the absence of air. Colombia is the third-largest global exporter of coke, with a significant portion of its exports going to the steel industry in countries such as Brazil, Mexico, and the United States. The country's high-quality coal reserves and proximity to major markets make it an important player in the global coal and coke trade. On the other hand, graphene and its derivative Graphene Oxide (GO) have unique properties that make them suitable for a wide range of commercial applications. Graphene has exceptional mechanical strength and high electrical conductivity, which make it an attractive material for a variety of electronic and structural applications. For example, graphene-based materials are being developed for use in flexible electronic devices, sensors, and high-strength composites. GO, on the other hand, is highly resistive but still retains exceptional mechanical strength. This makes it useful in applications where electrical conductivity is not necessary but mechanical strength and durability are important. Graphene production using current techniques can be expensive and inefficient, which limits its widespread adoption for commercial applications. However, new production methods, such as Liquid Phase Exfoliation (LPE), are being developed to address these challenges. LPE is a method for producing graphene and graphene oxide that involves using a liquid solvent to break apart graphite into individual graphene sheets. This method is more efficient and cost-effective than traditional methods such as mechanical exfoliation and chemical vapor deposition. In recent years, there has been increasing interest in using high-rank coal from Colombia as a raw material for graphene production using LPE. This is because high-rank coal from Colombia is known to have a high carbon content and low impurity levels, which makes it an ideal raw material for graphene production. Researchers have successfully produced GO using the LPE method and high-rank coal from Boavita, Colombia. This has the potential to significantly increase the supply of graphene and graphene oxide, making it more accessible for commercial applications. Additionally, using coal as a raw material for graphene production has the potential to create a new market for coal, which could benefit the Colombian economy. In order to synthesize GO, it is important to establish a suitable protocol for the grinding procedure and particle size selection. (i. more than 0.15 mm, ii. 0.15 mm to 0.05 mm, and iii. less than 0.05 mm) were defined. To compare the yield, the mineral matter removal procedure was carried out with a basic leaching bath. Coal oxidation was performed using the modified Hummers process, and GO was then obtained using LPE. This method has the following advantages:•It is feasible to produce GO from high-rank coal with acceptable quality and particulate size smaller than 0.15 mm, yields that are close to 5%, and flakes with fewer than 15 layers.•This approach also could eliminate dependence on graphite as the carbon feedstock for graphene production.•It is an alternative to manufacture GO from coal dust collected from mines.

Insights of Fe2O3 and MoO3 Electrodes for Electrocatalytic CO2 Reduction in Aprotic Media.

Transition metal oxides (TMO) have been successfully used as electrocatalytically active materials for CO2 reduction in some studies. Because of the lack of understanding of the catalytic behavior of TMOs, electrochemical methods are used to investigate the CO2 reduction in thin-film nanostructured electrodes. In this context, nanostructured thin films of Fe2O3 and MoO3 in an aprotic medium of acetonitrile have been used to study the CO2 reduction reaction. In addition, a synergistic effect between CO2 and the TMO surface is observed. Faradic cathodic processes not only start at lower potentials than those reported with metal electrodes, but also an increase in capacitive currents is observed, which is directly related to an increase in oxygen vacancies. Finally, the results obtained show CO as a product of the reduction.

Graphene Oxide: Study of Pore Size Distribution and Surface Chemistry Using Immersion Calorimetry.

In this work, the textural parameters of graphene oxide (GO) and graphite (Gr) samples were determined. The non-local density functional theory (NLDFT) and quenched solid density functional theory (QSDFT) kernels were used to evaluate the pore size distribution (PSD) by modeling the pores as slit, cylinder and slit-cylinder. The PSD results were compared with the immersion enthalpies obtained using molecules with different kinetic diameter (between 0.272 nm and 1.50 nm). Determination of immersion enthalpy showed to track PSD for GO and graphite (Gr), which was used as a comparison solid. Additionally, the functional groups of Gr and GO were determined by the Boehm method. Donor number (DN) Gutmann was used as criteria to establish the relationship between the immersion enthalpy and the parameter of the probe molecules. It was found that according to the Gutmann DN the immersion enthalpy presented different values that were a function of the chemical groups of the materials. Finally, the experimental and modeling results were critically discussed.

Preparation and Characterization of Graphene Oxide for Pb(II) and Zn(II) Ions Adsorption from Aqueous Solution: Experimental, Thermodynamic and Kinetic Study.

A thermodynamic and kinetic study of the adsorption process of Zn (II) and Pb (II) ions from aqueous solution on the surface of graphene oxide (GO) to establish the mechanisms of adsorbate-adsorbent interaction on this surface. The effect of pH on the retention capacity was studied and adsorption isotherms were determined from aqueous solution of the ions; once the experimental data was obtained, the kinetic and thermodynamic study of the sorption process was carried out. The data were fitted to the Langmuir, Freundlich, Dubinin-Raduskevich and Temkin isotherm models. The results showed that Zn(II) and Pb(II) on the GO adsorbing surface fitted the Langmuir model with correlation coefficients (R2) of 0.996. Kinetic models studied showed that a pseudo-second-order model was followed and thermodynamically, the process was spontaneous according to the values of Gibbs free energy (ΔG°). N2 adsorption isotherms were determined and modeled with the NLDFT (nonlocal density functional theory) and QSDFT (quenched solid density functional theory) kernels.

Automated versus Manual Oxygen Control with Different Saturation Targets and Modes of Respiratory Support in Preterm Infants.

OBJECTIVE: To determine the efficacy and safety of automated adjustment of the fraction of inspired oxygen (FiO2) in maintaining arterial oxygen saturation (SpO2) within a higher (91%-95%) and a lower (89%-93%) target range in preterm infants. STUDY DESIGN: Eighty preterm infants (gestational age [median]: 26 weeks, age [median] 18 days) on noninvasive (n = 50) and invasive (n = 30) respiratory support with supplemental oxygen, were first randomized to one of the SpO2 target ranges and then treated with automated FiO2 (A-FiO2) and manual FiO2 (M-FiO2) oxygen control for 24 hours each, in random sequence. RESULTS: The percent time within the target range was higher during A-FiO2 compared with M-FiO2 control. This effect was more pronounced in the lower SpO2 target range (62 ± 17% vs 54 ± 16%, P < .001) than in the higher SpO2 target range (62 ± 17% vs 58 ± 15%, P < .001). The percent time spent below the target or in hypoxemia (SpO2 <80%) was consistently reduced during A-FiO2, independent of the target range. The time spent above the target range or at extreme hyperoxemia (SpO2 >98%) was only reduced during A-FiO2 when targeting the lower SpO2 range (89%-93%). These outcomes did not differ between infants on noninvasive and invasive respiratory support. Manual adjustments were significantly reduced during A-FiO2 control. CONCLUSIONS: A-FiO2 control improved SpO2 targeting across different SpO2 ranges and reduced hypoxemia in preterm infants on noninvasive and invasive respiratory support. TRIAL REGISTRATION: ISRCTN 56626482.

Manipulación de embriones humanos: algunas objeciones / Human embryos manipulations: some objections

En este ensayo se entiende la ética como un saber práctico orientado hacia la “eupraxis”, el buen obrar. El acto médico prudente es respetuoso con la vida humana en condiciones de fragilidad. No todo lo que técnicamente se “puede” hacer, en realidad se “debe” hacer. La vida de los embriones humanos merece respeto pues son miembros de esta especie. En las aplicaciones de las tecnologías de manipulación embrionaria se causa de modo deliberado la muerte de aquellos, acción que es racionalmente inaceptable a la luz de la ética; por lo tanto, se debe ejercer objeción de conciencia ante tales actuaciones de la tecnociencia contemporánea.

Ethics is a practical knowledge, oriented to “eupraxis”, the good action. Prudential medical actions must behave respectfully toward human life in conditions of fragility. Not all thingsand actions that are technically possible are correct in terms of morality. Human embryos are members of our species; in the process of applying embryo manipulation techniques many of them are deliberately conducted to death. Such actions are rationally objectionableon an anthropological basis.

La medicina prenatal y la persona. Anotaciones desde una perspectiva bioética realista / La medicina prenatal y la persona. Anotaciones desde una perspectiva bioética realista

Se presenta una visión bioética sobre la condición personal del embrión humano, con base en su realidad ontológica. Se afirma la condición humana de la persona, intrínsecamente digna desde el momento del inicio de su existencia o trayectoria biográfica como cigoto. Además, se comentan de modo crítico algunas ideas utilitaristas-materialistas, con las que se niega la condición personal del embrión humano mediante la asignación de criterios “extrínsecos” y arbitrarios de dignidad: edad, período de desarrollo, voluntad de la madre o de terceros, condiciones clínicas, anatómicas o fisiológicas, determinaciones legislativas y otras.Asimismo, se llama la atención sobre los modos como en la práctica médica obstétrica contemporánea se han venido negando los aspectos ontológicos de la condición personal de todo ser humano, debido a presiones de orden utilitario. Existen tanto la negación “explícita” como la negación “tácita” de la realidad personal del no nacido.Se afirma que el respeto debido a la persona humana desde sus inicios –como a todo miembro de la especie– se debe a razones de orden “intrínseco”, inherentes a la condición personal de cada quien, sin discriminación alguna, dentro del concepto de la “autonomía teleológica” del embrión humano.

Síndrome Hellp: evolución histórica / HELLP syndrome: historical

Se presenta una revisión bibliográfica sobre el Síndrome de Elevación de Enzimas Hepáticas, Trombocitopenia y Hemolisis, complicación poco frecuente y grave de la hipertensión inducida por el embarazo. Se presenta igualmente un breve sumario, de sus aspectos fisiopatológicos con el objeto de servir como guía práctica para el clínico enfrentado a Pacientes con esto patología. Se hace un énfasis especial en el desarrollo histórico de los conocimientos pertinentes.

Tratamiento medico con metrotexate en embarazo ectopico / Medical treatment with methotrexate in ectopic pregnancy

Se presenta el caso de embarazo ectopico tucbarico de aproximadamente 8 semanas de gestacion en una paciente de 31 anos de edad quien fue sometida a tratamiento medico con metrotexate parenteral. Se observo mejoria de su cuadro por la evolucion clinica, controles ecograficos y controles de cuantificacion de fraccion beta de gonadotrofina corionica humana