Boger fluid flow through hyperbolic contraction microchannels

This paper was presented at the 3rd Micro and Nano Flows Conference (MNF2011), which was held at the Makedonia Palace Hotel, Thessaloniki in Greece. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, Aristotle University of Thessaloniki, University of Thessaly, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute.Boger fluids are characterized by their constant viscosity and elasticity and are very useful to study pure elastic flow behavior. In this paper we assess the potential of a microfluidic hyperbolic contraction as a device to measure the relaxation time of low viscosity polymer solutions, which are difficult to characterize in a conventional capillary break-up extensional rheometer. For this purpose we initially characterize the shear and extensional rheology of aqueous solutions of polyacrylamide (PAA) at different concentrations (400, 250, 125 and 50 ppm) with 1% (w/w) of NaCl, which result in low viscosity Boger fluids. Subsequently, flow visualizations of their flow through a microfluidic hyperbolic contraction were carried out in order to quantify the relation between their degree of elasticity and the vortex growth upstream of the microchannel.Fundação para a Ciência e a Tecnologia (FCT), COMPETE and FEDER through projects PTDC/ EQU-FTT/ 71800/2006, PTDC/EQUFTT/ 70727/2006, PTDC/EME-MFE/099109/ 2008, REEQ/928/EME/2005 and REEQ/298/EME/2005

Urban growth and loss of green spaces in the metropolitan areas of São Paulo and Mexico City: effects of land-cover changes on climate and water flow regulation

Urban green spaces provide ecosystem services that directly or indirectly benefit people, however, urban growth (especially in developing countries) generates the loss of these green areas and consequently of their ecosystem services. This paper aims to present the effects of land use and land cover changes in the last 30 years on two basic urban ecosystem services, water flow regulation and local and regional climate in two of main Latin American megacities (São Paulo and Mexico City). The study focuses on urban green spaces because they reduce the urban heat island effects, improve air quality, create habitats for biodiversity conservation, provide cultural services, and contribute to flooding prevention and groundwater conservation. A spatial analysis with the aid of geographic information systems was performed to assess (i) the urbanization process of the Metropolitan Areas of both cities over time; (ii) how this process generated changes in the land cover in both metropolises, and (iii) how these changes caused environmental negative impacts on ecosystem services. The loss of green areas as a consequence of urban expansion in the Metropolitan Areas of São Paulo and Mexico City changed the spatial distribution of urban heat island and increased the surface runoff, generating floods during the rainy periods. Our results suggest the urgent need for implementation of ecosystem-based spatial planning and ecological restoration of urban green areas in both studied cities to prevent further losses in ecosystem services and to improve the quality of life of urban inhabitants

Microchannels analogues for the study of viscoelastic fluid flows through porous media

This paper was presented at the 3rd Micro and Nano Flows Conference (MNF2011), which was held at the Makedonia Palace Hotel, Thessaloniki in Greece. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, Aristotle University of Thessaloniki, University of Thessaly, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute.This work studies the flow behavior and related pressure losses of viscoelastic polymer solutions in microchannels with two different sequences of contraction/expansion, disposed in a symmetric and an asymmetric arrangement, respectively. These microfluidic devices are proposed as simplified microchannel analogues for the flow of Newtonian and viscoelastic fluids through porous media. The results show that the symmetric configuration mimics the pressure gradient of these polymer solutions through a porous medium at low flow rates (below a critical Deborah number, Decr), while the asymmetric arrangement gives the asymptotic limit at high De values (above Decr) as a consequence of the intrinsic differences in the extensional rate profiles defined by each microgeometry.Fundação para a Ciência e a Tecnologia (FCT), COMPETE and FEDER through projects PTDC/ EQU-FTT/ 71800/ 2006, PTDC/EQUFTT/ 70727/ 2006, PTDC/ EME-MFE/ 99109/ 2008 and REEQ/ 262/ EME/ 2005

Shortcuts to adiabaticity in a time-dependent box

A method is proposed to drive an ultrafast non-adiabatic dynamics of an ultracold gas trapped in a box potential. The resulting state is free from spurious excitations associated with the breakdown of adiabaticity, and preserves the quantum correlations of the initial state up to a scaling factor. The process relies on the existence of an adiabatic invariant and the inversion of the dynamical self-similar scaling law dictated by it. Its physical implementation generally requires the use of an auxiliary expulsive potential analogous to those used in soliton control. The method is extended to a broad family of many-body systems. As illustrative examples we consider the ultrafast expansion of a Tonks-Girardeau gas and of Bose-Einstein condensates in different dimensions, where the method exhibits an excellent robustness against different regimes of interactions and the features of an experimentally realizable box potential.Comment: 6 pp, 4 figures, typo in Eq. (6) fixe

Evaluación del Proyecto Epikouros de Inserción Sociolaboral de Inmigrantes

El proyecto Epikouros del Ayuntamiento de Barcelona representa un modelo de servicio específico de orientación para la inserción sociolaboral dirigido a personas procedentes de la inmigración exterior y con situación socioeconómica deficitaria. El proyecto pretendía responder a las necesidad peculiares que estas personas tienen en su proceso de inserción sociolaboral en la ciudad de Barcelona. Su finalidad fue acercar a los colectivos, asociaciones y personas inmigrantes los distintos servicios de inserción sociolaboral normalizados del Ayuntamiento de Barcelona, a la vez que facilitar la coordinación y adaptación de éstos a las necesidades diferenciales que tiene esta población. El proyecto atendió a un total de 235 personas inmigrantes

Polysaccharide nanoparticles can efficiently modulate the immune response against anHIV peptide antigen

The development of an effective HIV vaccine continues to be a major health challenge since, so far, only the RV144 trial has demonstrated a modest clinical efficacy. Recently, the targeting of the 12 highly conserved protease cleavage sites (PCS1–12) has been presented as a strategy seeking to hamper the maturation and infectivity of HIV. To pursue this line of research, and because peptide antigens have low immunogenicity, we have included these peptides in engineered nanoparticles, aiming at overcoming this limitation. More specifically, we investigated whether the covalent attachment of a PCS peptide (PCS5) to polysaccharide-based nanoparticles, and their coadministration with polyinosinic:polycytidylic acid (poly(I:C)), improved the generated immune response. To this end, PCS5 was first conjugated to two different polysaccharides (chitosan and hyaluronic acid) through either a stable or a cleavable bond and then associated with an oppositely charged polymer (dextran sulfate and chitosan) and poly(I:C) to form the nanoparticles. Nanoparticles associating PCS5 by ionic interactions were used in this study as the control formulation. In vivo, all nanosystems elicited high anti-PCS5 antibodies. Nanoparticles containing PCS5 conjugated and poly(I:C) seemed to induce the strongest activation of antigen-presenting cells. Interestingly, T cell activation presented different kinetics depending on the prototype. These findings show that both the nanoparticle composition and the conjugation of the HIV peptide antigen may play an important role in the generation of humoral and cellular responsesThis work was supported by the National Institute of Allergy and Infectious Diseases of the National Institutes of Health (Award No. R01AI111805, Subaward No. 41795-02) and by the European Union’s Horizon 2020 research program (NanoPilot project, Grant Agreement No. 646142). T.G.D. acknowledges a predoctoral FPU grant from the Spanish Ministry of Education, Culture and Sports (Grant No. FPU14/05866)S

La vida de una cronista

Ser cronista es “…Una gran responsabilidad y compromiso porque cae el peso de representar afuera a la UAEM…” palabras contextualizadas de nuestra cronista institucional la M. en C. Ed. Ma. Del Consuelo Narváez Guerrero, quien a lo largo de los casi veinte años que tiene nuestro Centro Universitario UAEM Valle de Teotihuacán, ha laborado desde el 4 de septiembre de 2000 en nuestra casa universitaria

Evaluacion del flujo sanguíneo cerebral en fetos con cardiopatía fetal aislada, mediante el empleo de power doppler en tres dimensiones con correlación espacio-tiempo

Las cardiopatías congénitas (CC) permanecen como una importante causa de morbimortalidad infantil, es conocido que existe relación entre su diagnóstico y alteracion del neurodesarrollo, los factores directamente implicados en este proceso aun no están identificados, reconocerlos genera un impacto positivo que permitiría una adecuada asesoria genética y establecer mayor oportunidad desde el período neonatal. Objetivo: Evaluar el flujo sanguíneo cerebral en una cohorte de fetos con CC y fetos sanos en gestantes con características semejantes, Identificando los patrones circulatorios que determinen un pronóstico neonatal adverso, en los fetos con CC aislada. Metodologia estudio prospectivo de cohorte de gestantes ingresadas al programa de anomalías cardíacas congénitas (CC) y gestantes con fetos sanos, de la Unidad de Medicina Fetal, Clínica Universitaria Bolivariana (Medellín - Colombia), durante el periodo 2010 - 2016. Mediante la medición del flujo sanguíneo cerebral a través de la herramienta 3D Power Doppler (3DPwD). Resultados: Se analizaron 108 pacientes, 52 casos - 56 controles. La validez interna de la herramienta se realizó en fetos normales. El coeficiente de correlación intraclase, fue de 0.89 95% (IC 0.7574 - 0.9474). Pearson ρ 0.8867 y factor de corrección de sesgos Cb (Precisión) 0.9980. Las características maternas basales fueron similares en ambos grupos, en características perinatales, hubo diferencia estadisticamente significativa, la edad gestacional al nacer, una media de 37.6 (SD 1,1) en CC vs 38,6 (S D1.2) en sanos, (p 0.001). El peso al nacer 2816.6 gr (SD 443.9) vs 3106.8 (SD 281.3) respectivamente, (p 0.001), la via del parto fue cesárea, 63.5 % vs 12,5 % de los sanos (p 0.001). A los 2 grupos se les realizó dos evaluaciones de los indices de flujos sanguíneo cerebral, 24-26 y 34-36 semanas: índice de vascularización (VI), índice de flujo (FI) y el índice de vascularización - flujo (VFI). Las variables tuvieron una distribución normal, se encontró una diferencia estadísticamente significativa al evaluar el IVF en el segundo y tercer trimestre entre los recien nacidos con CC y sanos, un valor IVF Medio 36.06 (DS 6.92) vs 32.14 (DS 6.49) respectivamente, (p 0.003) y al final IVF 41.62 (DS 6.6) vs 38.74 (DS 4.49), (p 0.032). El IF del segundo trimestre, 12.26 (DS 6.499) vs 9.38 (DS 4.4) respectivamente, (p 0.009). El Doppler pulsado, el apgar, el tono, el color y los reflejos mostraron diferencia entre los grupos. Conclusion Los fetos con CC presentan procesos en útero que llevan a mayor riesgo de cambios hemodinámicos desfavorables y alteraciones en el neurodesarrollo. Identificar estos factores de riesgo en la vida prenatal pemitiría mecanismos estratégicos que lleven a una adaptación neonatal en mejores condiciones y plantear un seguimiento estricto que incluya el screening neurológico desde muy temprana edad.Congenital Cardiopathies (CC) remain as an important morbimortality cause in children, the relation between their diagnosis and an alteration of the neurodevelopement is known. Directly implicated factors in this process are still not identified, recognizing them generates a positive impact which would allow an adecuate genetic assessment and to stablish a more significant opportunity since the neonatal period. Objective: Evaluating Cerebral blood flow in a Cohort of fetuses with CC and healthy fetuses from pregnant women with similar characteristics, identifying circulatory patterns which determine an adverse neonatal prognosis in fetuses with isolated CC. Methodology: Cohort prospective study of pregnant women admitted to the Congenital Cardiac Anomalies program (CC) and pregnant women with healthy fetuses from the Fetal Medicine Unit, Clínica Universitaria Bolivariana (Medellín - Colombia) during the period 2010 - 2014 by measuring Cerebral blood flow through 3D Power Doppler (3DPwD) tool. Results: 108 patients were analyzed, 52 cases - 56 controls. The internal validity of the tool was carried out in normal fetuses. The intra class correlation coefficient was 0.89 95% (IC 0.7574 - 0.9474). Pearson ρ 0.8867 and a bias correction Factor Cb (Precision) 0.9980. Baseline maternal characteristics were similar in both groups; regarding perinatal characteristics, there was a statistically significant difference, gestational age at birth, median of 37.6 (SD 1,1) in CC vs 38,6 (S D1.2) in healthy, (p 0.001). weight at birth 2816.6 grs (SD 443.9) vs 3106.8 grs (SD 281.3), respectively, (p 0.001), the delivery route was cesarean, 63.5 % vs 12,5 % of the healthy (p 0.001). Both groups underwent two Cerebral blood flow index evaluations, 24-26 and 34-36 weeks: vascularization index (VI), flow index (FI) and vascularization - flow index (VFI). Variables had a normal distribution, a statistically significant difference was found when evaluating the VFI in the second and third trimester among newborns with CC and the healthy, a mean VFI value of 36.06 (DS 6.92) vs 32.14 (DS 6.49), respectively, (p 0.003) and in the end VFI 41.62 (DS 6.6) vs 38.74 (DS 4.49), (p 0.032). The FI of the second trimester, 12.26 (DS 6.499) vs 9.38 (DS 4.4) respectively, (p 0.009). Pulsed Doppler, the apgar, tone, color and reflexes showed difference between the groups. Conclusion: Fetuses with CC present in uterus processes which lead to a higher risk of hemodynamic unpromising changes and neurodevelopment alterations. Identifying these risk factors in the prenatal life will allow strategic mechanisms leading to a neonatal adaptation in better conditions and to set out a strict follow up which includes neurologic screening from an early age