Kinetic study of the catalytic cracking of waste motor oil using biomass-derived heterogeneous catalysts.

Herein, biochar from biomass residues is demonstrated as active materials for the catalytic cracking of waste motor oil into diesel-like fuels. Above all, alkali-treated rice husk biochar showed great activity with a 250% increase in the kinetic constant compared to the thermal cracking. It also showed better activity than synthetic materials, as previously reported. Moreover, much lower activation energy (185.77to293.48kJmol) for the cracking process was also obtained. According to materials characterization, the catalytic activity was more related to the nature of the biochar's surface than its specific surface area. Finally, liquid products complied with all the physical properties defined by international standards for diesel-like fuels, with the presence of hydrocarbons chains between C10-C27 similar to the ones obtained in commercial diesel.

Simple Preparation of Metal-Impregnated FDM 3D-Printed Structures.

Modifying the natural characteristics of PLA 3D-printed models is of interest in various research areas in which 3D-printing is applied. Thus, in this study, we describe the simple impregnation of FDM 3D-printed PLA samples with well-defined silver nanoparticles and an iron metal salt. Quasi-spherical and dodecahedra silver particles were strongly attached at the channels of 3D-printed milli-fluidic reactors to demonstrate their attachment and interaction with the flow, as an example. Furthermore, Fenton-like reactions were successfully developed by an iron catalyst impregnated in 3D-printed stirrer caps to induce the degradation of a dye and showed excellent reproducibility.

Combining autoclave and LCWM reactor studies to shed light on the kinetics of glucose oxidation catalyzed by doped molybdenum-based heteropoly acids.

In this work we combined kinetic studies for aqueous-phase glucose oxidation in a high-pressure autoclave setup with catalyst reoxidation studies in a liquid-core waveguide membrane reactor. Hereby, we investigated the influence of Nb- and Ta-doping on Mo-based Keggin-polyoxometalates for both reaction steps independently. Most importantly, we could demonstrate a significant increase of glucose oxidation kinetics by Ta- and especially Nb-doping by factors of 1.1 and 1.5 compared to the classical HPA-Mo. Moreover, activation energies for the substrate oxidation step could be significantly reduced from around 80 kJ mol-1 for the classical HPA-Mo to 61 kJ mol-1 for the Ta- and 55 kJ mol-1 for the Nb-doped species, respectively. Regarding catalyst reoxidation kinetics, the doping did not show significant differences between the different catalysts.

[Premature birth in patient with cervix incompetence and history of myasthenia gravis]. / Parto prematuro en paciente con incompetencia cervical y antecedentes de miastenia gravis.

Cervical incompetence it's a dilatation of the cervix during the third trimester of pregnancy that ends with the interruption of it. The incidence in Chile is about 0.1-2% of the total pregnancies and it's one of the causes of preterm birth. A 34 years old pregnant patient. Timectomized at age 18 to treat her miastenia gravis, previously trated with medication, had 4 previous preterm labours all of them under 25 weeks and vaginal births. All fetuses died postpartum. A cerclage was made during the third, fourth and fifth pregnancies. She didn't present hypertension during the gestation and no cervical diameter under 15mm. Since the fourth gestation the following tests are taken: Antifosfolipidic antibodies, APTT,PT. All the results are either normal or negative. Microbial cultures were negative. No amniocentesis was made. A McDonald cervical cerclage was made during pregnancies number 3, 4 and 5 on the 16th week to delay the labor. Also oral micronized progesterone, on a 400mg/24 hours dosis, was administered to avoid preterm birth. On the 24th week the pharmacological treatment started including Intramuscular Betamethasone, 12 mg/24 hours (2 doses), to induce lung maturity on the fetus. It is thought that the administration of progesterone could have improved the situation of the patient, because it acts as a labour repressants. The use of cerclage could have helped, but the factors that may influence the effectiveness of this method are unknown. Perhaps there is some immunologic factor associated with the miastenia gravis that alters the normal course of pregnancy.