PLLA/ZnO nanocomposites: dynamic surfaces to harness cell differentiation

This work investigates the effect of the sequential availability of ZnO nanoparticles, (nanorods of ∼40 nm) loaded within a degradable poly(lactic acid) (PLLA) matrix, in cell differentiation. The system constitutes a dynamic surface, in which nanoparticles are exposed as the polymer matrix degrades. ZnO nanoparticles were loaded into PLLA and the system was measured at different time points to characterise the time evolution of the physicochemical properties, including wettability and thermal properties. The micro and nanostructure were also investigated using AFM, SEM and TEM images. Cellular experiments with C2C12 myoblasts show that cell differentiation was significantly enhanced on ZnO nanoparticles—loaded PLLA, as the polymer degrades and the availability of nanoparticles become more apparent, whereas the release of zinc within the culture medium was negligible. Our results suggest PLLA/ZnO nanocomposites can be used as a dynamic system where nanoparticles are exposed during degradation, activating the material surface and driving cell differentiation

Cluster analysis to validate the sustainability label of stock indices: An analysis of the inclusion and exclusion processes in terms of size and ESG ratings

Sustainability stock indices play an important role in guiding socially responsible funds to their constituents. Thus, to find out whether the term sustainability is more than just a label, we analyze the inclusion and exclusion criteria applied by sustainability indices, and we compare them with those applied by conventional indices. We analyze the level of sustainability and size of the companies included in and excluded from five sustainability indices compared to a control group of 11 conventional indices. Our results show that the level of sustainability influences the inclusion process and, to a lesser extent, the exclusion process of the five FTSE4Good indices. However, we find similar results for several conventional indices. In addition, the size criterion dominates the sustainability criterion in the inclusion and exclusion processes of sustainability indices like in conventional indices. Further, we use different cluster algorithms to determine that the inclusion and exclusion processes of four of the five sustainability indices are different from those of the conventional indices. Our results validate the use of the “sustainability” label for four of five sustainability indices but also show that further differentiation between sustainability and conventional indices is needed

Alkohola eta alkoholimetroa

Kimikak eta garapen teknologikoak gure eguneroko bizitzan eman ahal diguten laguntza azaldu nahi dugu artikulu honetan adibide baten bidez, hain zuzen ere, edan dugun alkohola-maila neurketaren bidez. Antzinean erredox erreakzioan oinarritutako prozedura erabiltzen ba zen ere, gaur egun alkoholimetroa deituriko neurgailu zehatza erabiltzen da

Polymeric Shape-Memory Micro-Patterned Surface for Switching Wettability with Temperature

An innovative method to switch the wettability of a micropatterned polymeric surface by thermally induced shape memory effect is presented. For this purpose, first polycyclooctene (PCO) is crosslinked with dycumil peroxide (DCP) and its melting temperature, which corresponds with the switching transition temperature (Ttrans), is measured by Dynamic Mechanical Thermal Analysis (DMTA) in tension mode. Later, the shape memory behavior of the bulk material is analyzed under different experimental conditions employing a cyclic thermomechanical analysis (TMA). Finally, after creating shape memory micropillars by laser ablation of crosslinked thermo-active polycyclooctene (PCO), shape memory response and associated effect on water contact angle is analyzed. Thus, deformed micropillars cause lower contact angle on the surface from reduced roughness, but the original hydrophobicity is restored by thermally induced recovery of the original surface structureThe authors thank the Basque Country Government for financial support (Ayudas para apoyar las actividades de los grupos de investigacion del sistema universitario vasco, IT718-13). Technical and human support provided by SGIKER (UPV/EHU, MICINN, GV/EJ, ERDF and ESF) is gratefully acknowledged

Volatilidad implícita y ecuación de Black&Sholes: Vega, Gamma, Delta y Theta.

La fórmula desarrollada por Black&Sholes es una fórmula compleja utilizada para la valoración de opciones europeas. Para operar con este tipo de productos financieros es indispensable poseer una comprensión avanzada de esta fórmula. En este trabajo se ha realizado un estudio de las derivadas parciales de esta fórmula - Vega, Delta, Gamma y Theta- y como estas reaccionan ante variaciones de la volatilidad, del precio del subyacente y del paso del tiempo. Este trabajo ofrecerá al lector herramientas analíticas de utilidad para desarrollar estrategias de gestión activa mediante el uso de opciones. Para desarrollar correctamente una estrategia de inversión es fundamental entender el escenario de sensibilidades en el que se puede operar en un momento dado. El trabajo finalizará con la introducción del concepto de volatilidad implícita. Este concepto enriquecerá lo aprendido hasta el momento, pero dejará en evidencia que hay más aspectos que se deben de tener en cuenta a la hora de invertir con opciones a parte de las implicaciones matemáticas de la fórmula de Black&Sholes. La realidad es extremadamente compleja y este trabajo es una primera aproximación al apasionante y complejo mundo de la “Ingeniería Financiera”

Patronato agrícola “Visconde de Mauá”: da sua origem ao IFSULDEMINAS - Campus Inconfidentes

A história é uma ciência fundamental para a análise da sociedade. Através dela é possível reconhecer os esforços de muitos homens que lutaram para dialogar com o tempo e realizaram grandes feitos contribuindo com o desenvolvimento da humanidade. No que diz respeito ao aspecto educacional não é diferente. A educação é condição essencial não só para a ampliação do conhecimento, mas, sobretudo, para uma construção social. Assim através de uma análise documental pode-se levantar historicamente, a trajetória do Patronato Agrícola “Visconde de Mauá” até a origem do Instituto Federal de Educação Ciência e Tecnologia do Sul de Minas Gerais (IFSULDEMINAS) - Campus Inconfidentes. Pode ser verificado que o desenvolvimento do município de Inconfidentes, sul de Minas Gerais, está entrelaçado com a história educacional, ofertada ao longo do tempo que permitiu não só formar os jovens para a sociedade, mas, contribuiu significantemente para que o município se destacasse como um polo importante na área educacional. Palavras-chave: História. Evolução. Educação. IFSULDEMINAS

Personas sin hogar en Zaragoza: Comparativa de los datos de 2010 a 2012

Comparativa y evolución de los datos obtenidos a través de los II recuentos de personas sin hogar realizados en Zaragoz

Algunas claves y textos de Concepción Arenal para un debate inacabado

Este apartado sirve para finalizar este número monográfico. Consta de dos artículos independientes y complementarios. Luis Vilas sobre “El Visitador del pobre” y Mª José Lacalzada sobre las “Cartas a un señor”. En ambos la voz de Concepción Arenal queda recogida con amplitud, contextualizada en nuestras intervenciones y preocupaciones presentes, y sobre todo dejando la ocasión a que otras muchas personas puedan aproximarse a ella

Hybrid Organic-Inorganic Membranes for Photocatalytic Water Remediation

Mismanagement, pollution and excessive use have depleted the world’s water resources, producing a shortage that in some territories is extreme. In this context, the need for potable water prompts the development of new and more efficient wastewater treatment systems to overcome shortages by recovering and reusing contaminated water. Among the water treatment methods, membrane technology is considered one of the most promising. Besides, photocatalytic degradation has become an attractive and efficient technology for water and wastewater treatment. However, the use of unsupported catalysts has as its main impediment their separation from the water once treated. With this, providing the membranes with this photocatalyzed degradation capacity can improve the application of photocatalysts, since in many cases their application improves their recovery and reuse. This review describes the general photocatalytic processes of the main inorganic nanoparticles used as fillers in hybrid polymeric membranes. In addition, the most recent hybrid organic–inorganic membranes are reviewed. Finally, the membranes formed by metal–organic frameworks that can be considered one of the newest and most versatile developments are described.This research was funded by MINECOG (MAT2017-89553-P), UPV/EHU and Fundación Vital funding within the project “PROYECTOS DE INVESTIGACIÓN UPV/EHU-FUNDACIÓN VITAL FUNDAZIOA 2020” (VITAL20/26) and Basque Government (ELKARTEK, KK-2021/00082; KK-2020/00019)

Energetic study of ultrasonic wettability enhancement

[EN]Many industrial and biological interfacial processes, such as welding and breathing depend directly on wettability and surface tension phenomena. The most common methods to control the wettability are based on modifying the properties of the fluid or the substrate. The present work focuses on the use of high-frequency acoustic waves (ultrasound) for the same purpose. It is well known that ultrasound can effectively clean a surface by acoustic cavitation, hence ultrasonic cleaning technology. Besides the cleaning process itself, many authors have observed an important wettability enhancement when liquids are exposed to low and high (ultrasonic) frequency vibration. Ultrasound goes one step further as it can instantly adjust the contact angle by tuning the vibration amplitude, but there is still a lack of comprehension about the physical principles that explain this phenomenon. To shed light on it, a thermodynamic model describing how ultrasound decreases the contact angle in a three-phase wetting system has been developed. Moreover, an analytical and experimental research has been carried out in order to demonstrate that ultrasound is an important competitor to surfactants in terms of energy efficiency and environmental friendliness.The projects leading to this research have received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement N° 654479 WASCOP and N°792103 SOLWARIS