A scalable 3D printed bioreactor for the expansion of anchorage-dependent stem cells

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Understanding the Internationalization of Latin American Enterprises

This paper purpose is to advance the understanding of Latin American multinationals internationalization. Using disaggregated data and differentiating the behavior between private-owned and state-owned multinational enterprises from nine Latin American countries, we analyze this matter at firm, industry and country level. We find that Latin American firms prefer to invest in the same region, nevertheless, the US appears like the most frequent country where these MNEs allocate its subsidiaries. We show that the research and development intensity level of the largest enterprises from Latin America is not high, that most of them are privately-owned and they are performing in a wide variety of industries

ESTADO DE LA CUESTIÓN SOBRE LAS CRÍTICAS A LA AGRICULTURA ORGÁNICA

This article discusses the main criticisms of organic agriculture. The methodology is qualitative descriptive narrative review, with elements of simplification and dramatization to highlight key points. The purpose of the study was to analyze what has submitted the relevant literature on the discussion of the main criticisms of organic farming and what answers are given to these criticisms. For this purpose 46 articles were analyzed, in magazines and collections of digital databases. The qualitative approach allowed the identification of the main arguments and we decided to group them into two categories: (i) criticism of organic production and (ii) criticism of organic marketing. Finally, the article considers that organic agriculture can play an important role for the global food, however, we pointed the risk that in the future organic agriculture might lose its fundamental principles of serving mankind and the environment

Diseño aerodinámico de un UAV con aplicación en fumigación agrícola.

El presente trabajo fue realizado con el fin de obtener el título de Maestro en Ciencias de Ingeniería Aeronáutica, con enfoque a Dinámica de Vuelo. A continuación en este se muestra el planteamiento para la solución de uno de los problemas más grandes en la pérdida de cosechas. Dicha solución es la prevención y exterminación de plagas mediante la fumigación aérea. En esta tesis, se detalla el diseño aerodinámico de un vehículo aéreo no tripulado (UAV por sus siglas en inglés), como su título lo dice. Para poder llegar al resultado final, se debió realizar el planteamiento del problema, definiendo los objetivos de la aeronave, de tal forma que la aeronave no tripulada pudiera cumplir con las necesidades que se tienen en la vida cotidiana dentro de la agricultura y además, sin descuidar la aeronavegabilidad del modelo. Por esta razón se comenzó por hacer el planteamiento de la misión, donde se denotaron, limitaron y propusieron los diferentes valores iniciales y de frontera, mediante una investigación documental de las necesidades de los agricultores mexicanos para realizar la tarea de fumigación, así como mediante el estudio estadístico de aviones equivalentes en operación. De esta manera se pudo proponer una estructura, la cual fue modificada mediante la aplicación de códigos diseñados en Matlab, haciendo un enlace con el programa computacional AVL. Una vez que se plantearon los requerimientos esenciales de la misión, se pudo proceder al dimensionamiento, el cual cuenta con cálculos necesarios para definir el peso máximo de despegue, el cual consta de la determinación de la carga útil, peso del fuselaje, peso del combustible necesario para realizar un vuelo completo, etc. Lo anterior fue realizado con métodos matemáticos y computacionales mediante un acoplamiento de funciones que en conjunto podían realizar esta tarea, así como algunas otras, como determinar diversas configuraciones del UAV. En este proceso se consideró como referencia el centro de gravedad de la aeronave, con lo cual se pudieron definir las configuraciones, ala, fuselaje, empenaje del modelo. Para alimentar los datos en los códigos mencionados, previamente se realizó el análisis aerodinámico de perfiles alares, formas de ala y formas del fuselaje mediante Computational Fluid Dynamics (CFD).

EFICACIA Y SEGURIDAD DEL USO DE NORADRENALINA EN INFUSIÓN VS NORADRENALINA EN BOLOS COMO TRATAMIENTO PARA LA HIPOTENSIÓN SECUNDARIA A BLOQUEO NEUROAXIAL EN PACIENTES SOMETIDAS A CESÁREA.

En pacientes sometidas a cesárea la hipotensión secundaria a bloqueo neuroaxial constituye un reto para el anestesiólogo y se convierte en piedra angular del manejo anestésico, por lo que contar con tratamientos eficaces y seguros son parte de un manejo integral del binomio. Evaluar la eficacia y seguridad del uso de noradrenalina para tratamiento de la hipotensión secundaria a bloqueo neuroaxial en pacientes sometidas a cesárea. Se realizó un ensayo clínico aleatorizado donde se incluyeron pacientes operadas de cesárea de acuerdo a los criterios de inclusión. Se dividió en dos grupos: “grupo 0” pacientes a los que se administró infusión de noradrenalina dosis de 0.05 mcg/kg/m posterior a hipotensión por bloqueo neuroaxial y “grupo 1” pacientes a los que se administró noradrenalina dosis bolo de 8 mcg a los 5 minutos posterior a la hipotensión por bloqueo neuroaxial, con dosis subsecuentes. Se registraron signos vitales a los 5, 10 y 15 minutos posterior a la administración del fármaco con un valor de p <0.001 en el grupo de 5 minutos a favor del grupo 1, sin diferencia signficativa a los 10 y 15 minutos. La administración de Noradrenalina en bolos resultó ser eficaz y segura a dosis de 8 mcg vs infusion a dosis 0.05 mcg/kg/m sin demostrar efectos adversos en este estudio.UAEM, el autor

Effect of Thevetia peruviana on murine-induced obesity

Background: Obesity is considered a multifactorial disease that has importantly increased the development of chronic degenerative diseases. Drugs available for treating obesity have the inconvenience of producing side effects of importance. In Mexican traditional medicine, the seeds of Thevetia peruviana have been widely employed for weight reduction.Materials and Methods: The effect produced by different extracts of T. peruviana on MonoSodium Glutamate (MSG)-induced obesity in mice was evaluated. A chemical analysis oriented toward the identification of the chemical compounds contained in the active extract was carried out.Results: Oral administration of the hexanic extract of T. peruviana (for 7 weeks) was capable of diminishing weight gain by up to 24.1% in the mice without observing the development of resistance to insulin. Median lethal dose of the hexanic and Ethyl Acetate (EtOAc) extracts was &gt;2 g/kg. By utilizing bio-assay guided fractionation, eight secondary metabolites were purified and characterized.Conclusion: The hexanic extract obtained from Thevetia peruviana seeds was capable of reducing weight gain in mice with induced obesity. In addition, this extract showed good response to the glucose tolerance test, was able to avoid the development of insulin resistance, and also substantially increased serum adiponectin levels. Eight low-polarity compounds were identified in the active fraction. This species could be considered for ongoing investigation as a potential option to reduce obesityKeywords: Obesity, Thevetia peruviana, medicinal plants, body weight, adiponectin, monosodium glutamate, sterol

Inhibición de la actividad de acetilcolinesterasa por el extracto hidroalcohólico y sus fracciones de Bouvardia ternifolia (Cav.) Shcltdl (Rubiaceae)

El extracto hidroalcohólico (BtHA) y fracciones provenientes de Bouvardia ternifolia fueron evaluadas como inhibidores de la enzima acetilcolinesterasa  utilizando el método enzimático propuesto por Ellman. BtHA  inhibe a la enzima de manera competitiva (IC50 = 0.6 g/ml); la fracción de acetato de etilo  (BtF-AcOEt) provoca una inhibición mixta (IC50 = 0.96 g/ml). La fracción insoluble en metanol (Bt-Faq-1) mostró una inhibición tipo mixta (CI50 = 0.96  g/ml). Finalmente la fracción soluble en metanol, Bt-Faq-2, inhibe a la enzima presentando una inhibición mixta que corresponde a un sistema C5 (  = 0.740  and  = 0.842). Mediante HPLC se detectó rutina, quercetina, canferol y ácido ursólico la concentración de estos compuestos fue diferente en cada fracción

Use of antifungal Saponin SC-2 of Solanum chrysotrichum for the treatment of vulvovaginal candidiasis: in vitro studies and clinical experiences

Saponin SC-2 from Solanum chrysotrichum showed antifungal activity, demonstrated in vitro, which inhibited the growth of dermatophytes, and in vivo, to be effective in the treatment against tinea pedis and pityriasis capitis. Fungistatic and fungicidal activity of saponin SC-2 on Candida albicans and other Candida species, fluconazole and ketoconazole resistaent strains was demostrated. SC-2-associated ultrastructural alterations in several Candida species were observed. An exploratoryclinical, randomized, double-blind, and controlled ketoconazole study of ketoconazole was conducted with the aim of assessing the effectiveness and tolerability of an herbal medicinal product containing SC-2, on women with Vulvovaginal candidiasis (VVC). The results exhibited a percentage of therapeutic clinical effectiveness similar to that of ketoconazole (X2, p .0.30), but obtained a smaller percentage of mycological effectiveness, and 100% tolerability. In conclusion, saponin SC-2 possesses fungicidale and fungistatic activity on Candida albicans and other multi resistant Candida species, causes morphological changes and fungal death, and it is an alternative therapy for the treatment of VVC.Key words: Solanum chrysotrichum, saponins, antifungal activity, vulvovaginal candidiasis, alternative therapy

Chemical characterization of a hypoglycemic extract from Cucurbita ficifolia bouche that induces liver glycogen accumulation in diabetic mice

Background: The aqueous extract of Cucurbita ficifolia (C. ficifolia) fruit has demonstrated hypoglycemic effect, which may be attributed to some components in the extract. However, the major secondary metabolites in this fruit have not yet been identified and little is known about its extra-pancreatic action, in particular, on liver carbohydrate metabolism. Therefore, in addition to the isolation and structural elucidation of the principal components in the aqueous extract of C. ficifolia, the aim of this study was to determine whether or not the hypoglycemic effect of the aqueous extract of Cucurbita ficifolia (C. ficifolia) fruit is due to accumulation of liver glycogen in diabetic mice.Materials and Methods: The aqueous extract from fruit of C. ficifolia was fractionated and its main secondary metabolites were purified and chemically characterized (NMR and GC-MS). Alloxan-induced diabetic mice received daily by gavage the aqueous extract (30 days). The liver glycogen content was quantified by spectroscopic method and by PAS stain; ALT and AST by spectrometric method; glycogen synthase, glycogen phosphorylase and GLUT2 by Western blot; the mRNA expression of GLUT2 and glucagon-receptor by RT-PCR; while serum insulin was quantified by ELISA method. A liver histological analysis was also performed by H&amp;E stain.Results: Chemical fingerprint showed five majoritarian compounds in the aqueous extract of C. ficifolia: p-coumaric acid, p-hydroxybenzoic acid, salicin, stigmast-7,2,2-dien-3-ol and stigmast-7-en-3-ol. The histological analysis showed accumulation of liver glycogen. Also, increased glycogen synthase and decreased glycogen phosphorylase were observed. Interestingly, the histological architecture evidenced a liver-protective effect due the extract.Conclusion: Five compounds were identified in C. ficifolia aqueous extract. The hypoglycemic effect of this extract may be partially explained by liver glycogen accumulation. The bioactive compound responsible for the hypoglycemic effect of this extract will be elucidated in subsequent studies.Keywords: Cucurbita ficifolia, Cucurbitaceae, liver glycogen, hypoglycemic plants, p-coumaric acid, salicin, p-hydroxybenzoic aci