América Latina. Los derechos y las prácticas ciudadanas a la luz de los movimientos populares

A partir, fundamentalmente, de los análisis de caso y los datos que ha sistematizado el Observatorio Social de América Latina (OSAL), nuestra propuesta gira en torno a dos preguntas centrales: ¿qué características presenta la noción de ciudadanía en las luchas sociales latinoamericanas recientes?, y ¿qué importancia adquiere dicha dimensión para la consecución de un propósito democrático? Buscando responder ambas, hemos dividido la exposición en tres apartados. En el primero se exploran los elementos que han favorecido el reposicionamiento de la noción de ciudadanía, dentro del horizonte y discurso de las movilizaciones que a partir del año 2000 han aparecido en distintos puntos del subcontinente. En el segundo, se examinan las características más relevantes que desde nuestro punto de vista hilvanan su diversidad. Y, finalmente, en el último se desarrollan las razones por las cuales consideramos que la noción de ciudadanía ocupa un lugar estratégico en la lucha social latinoamericana de este inicio de milenio.Presentación | 9 Lucha social y derechos ciudadanos en América Latina Margarita Favela Gavia y Diana Guillén | 21 Conflictos y tensiones en torno del Estado ampliado en América Latina: Brasil y México entre la crisis orgánica del Estado y el problema de la hegemonía Lucio Oliver | 51 Movimiento-partido: el caso del Movimiento de los Trabajadores sin Tierra (MST) en Brasil Adelita Neto Carleial | 81 Seguridad alimentaria y diseño de nuevos espacios públicos en Brasil Elza Maria Franco Braga | 111 Democracia y ciudadanía en el movimiento lopezobradorista Carlos Figueroa Ibarra y Octavio H. Moreno | 129 Venciendo el miedo: retoños de movimientos sociales en el contexto de la recuperación democrática en Perú (2000-2006) Fabiola Escárzaga | 155 Reflexiones sobre la democracia y el significado de un gobierno de los movimientos sociales en Bolivia Dunia Mokrani Chávez | 191 Entre la izquierda partidista y la izquierda social: el movimiento étnico maya y las opciones político-partidistas en Guatemala Luis Fernando Mack, Máximo Ba Tiul e Ivonne Solórzano | 215 Movimiento social y proceso político en Haití (1986-2006) Alejandro Álvarez Martínez | 24

Dosimetry and calorimetry performance of a scientific CMOS camera for environmental monitoring

This paper explores the prospect of CMOS devices to assay lead in drinking water, using calorimetry. Lead occurs together with traces of radioisotopes, e.g.,210 Pb, producing γ-emissions with energies ranging from 10 keV to several 100 keV when they decay; this range is detectable in silicon sensors. In this paper we test a CMOS camera (OXFORD INSTRUMENTS Neo 5.5) for its general performance as a detector of X-rays and low energy γ-rays and assess its sensitivity relative to the World Health Organization upper limit on lead in drinking water. Energies from 6 keV to 60 keV are examined. The CMOS camera has a linear energy response over this range and its energy resolution is for the most part slightly better than 2%. The Neo sCMOS is not sensitive to X-rays with energies below ∼ 10 keV. The smallest detectable rate is 40 ± 3 mHz, corresponding to an incident activity on the chip of 7 ± 4 Bq. The estimation of the incident activity sensitivity from the detected activity relies on geometric acceptance and the measured efficiency vs. energy. We report the efficiency measurement, which is 0.08(2)% (0.0011(2)%) at 26.3 keV (59.5 keV). Taking calorimetric information into account we measure a minimal detectable rate of 4 ± 1 mHz (1.5 ± 0.1 mHz) for 26.3 keV (59.5 keV) γ-rays, which corresponds to an incident activity of 1.0 ± 0.6 Bq (57 ± 33 Bq). Toy Monte Carlo and Geant4 simulations agree with these results. These results show this CMOS sensor is well-suited as a γ-and X-ray detector with sensitivity at the few to 100 ppb level for210 Pb in a sample

Generation of an in vitro 3D PDAC stroma rich spheroid model

Pancreatic ductal adenocarcinoma (PDAC) is characterized by a prominent desmoplastic/stromal reaction, which contributes to the poor clinical outcome of this disease. Therefore, greater understanding of the stroma development and tumor-stroma interactions is highly required. Pancreatic stellate cells (PSC) are myofibroblast-like cells that located in exocrine areas of the pancreas, which as a result of inflammation produced by PDAC migrate and accumulate in the tumor mass, secreting extracellular matrix components and producing the dense PDAC stroma. Currently, only a few orthotopic or ectopic animal tumor models, where PDAC cells are injected into the pancreas or subcutaneous tissue layer, or genetically engineered animals offer tumors that encompass some stromal component. Herein, we report generation of a simple 3D PDAC in vitro micro-tumor model without an addition of external extracellular matrix, which encompasses a rich, dense and active stromal compartment. We have achieved this in vitro model by incorporating PSCs into 3D PDAC cell culture using a modified hanging drop method. It is now known that PSCs are the principal source of fibrosis in the stroma and interact closely with cancer cells to create a tumor facilitatory environment that stimulates local and distant tumor growth. The 3D micro-stroma models are highly reproducible with excellent uniformity, which can be used for PDAC-stroma interaction analysis and high throughput automated drug-screening assays. Additionally, the increased expression of collagenous regions means that molecular based perfusion and cytostaticity of gemcitabine is decreased in our Pancreatic adenocarcinoma stroma spheroids (PDAC-SS) model when compared to spheroids grown without PSCs. We believe this model will allow an improved knowledge of PDAC biology and has the potential to provide an insight into pathways that may be therapeutically targeted to inhibit PSC activation, thereby inhibiting the development of fibrosis in PDAC and interrupting PSC-PDAC cell interactions so as to inhibit cancer progression

Electrochemical Oxidation of Dihydronicotinamide Adenine Dinucleotide at Nitrogen-Doped Carbon Nanotube Electrodes

Nitrogen-doped carbon nanotubes (N-CNTs) substantially lower the overpotential necessary for dihydronicotinamide adenine dinucleotide (NADH) oxidation compared to nondoped CNTs or traditional carbon electrodes such as glassy carbon (GC). We observe a 370 mV shift in the peak potential (<i>E</i>_p) from GC to CNTs and another 170 mV shift from CNTs to 7.4 atom % N-CNTs in a sodium phosphate buffer solution (pH 7.0) with 2.0 mM NADH (scan rate 10 mV/s). The sensitivity of 7.4 atom % N-CNTs to NADH was measured at 0.30 ± 0.04 A M^–1 cm^–2, with a limit of detection at 1.1 ± 0.3 μM and a linear range of 70 ± 10 μM poised at a low potential of −0.32 V (vs Hg/Hg₂SO₄). NADH fouling, known to occur to the electrode surface during NADH oxidation, was investigated by measuring both the change in <i>E</i>_p and the resulting loss of electrode sensitivity. NADH degradation, known to occur in phosphate buffer, was characterized by absorbance at 340 nm and correlated with the loss of NADH electroactivity. N-CNTs are further demonstrated to be an effective platform for dehydrogenase-based biosensing by allowing glucose dehydrogenase to spontaneously adsorb onto the N-CNT surface and measuring the resulting electrode’s sensitivity to glucose. The glucose biosensor had a sensitivity of 0.032 ± 0.003 A M^–1 cm^–2, a limit of detection at 6 ± 1 μM, and a linear range of 440 ± 50 μM

Investigating the Electrocatalytic Oxidation of Dihydronicotinamide Adenine Dinucleotide at Nitrogen-Doped Carbon Nanotube Electrodes: Implications to Electrochemically Measuring Dehydrogenase Enzyme Kinetics

Nitrogen-doped carbon nanotubes (N-CNTs) have been shown to be electrocatalytic toward the oxidation of dihydronicotinamide adenine dinucleotide (NADH), the reduced form of the coenzyme necessary for enzymatic turnover in NAD⁺-dependent dehydrogenases. The observed oxidation potential of the electrocatalyst, however, still shows a significant overpotential, suggesting that even for effective electrocatalysts, electrooxidation may be kinetically controlled. We demonstrate using the Koutecky–Levich rotating disk electrode technique that the observed electron transfer rate constant (<i>k</i>_obs) is a function of potential over a wide potential window; however, <i>k</i>_obs could only be accurately measured for a portion of that window for the electrocatalytic N-CNTs. More importantly, electrochemically measured enzyme kinetics, acquired after adsorption of glucose dehydrogenase onto the N-CNTs, are never independent of potential, even when the electron transfer rate constant is too fast to measure by the rotating disk technique. Thus, electrochemically obtained kinetics (e.g., <i>K</i>_M^app and <i>V</i>_max) are actually measuring the electrochemical kinetics of NADH oxidation at the electrode surface, rather than the spontaneous and potential-independent enzymatic turnover

H₂O₂ Detection at Carbon Nanotubes and Nitrogen-Doped Carbon Nanotubes: Oxidation, Reduction, or Disproportionation?

The electrochemical behavior of hydrogen peroxide (H₂O₂) at carbon nanotubes (CNTs) and nitrogen-doped carbon nanotubes (N-CNTs) was investigated over a wide potential window. At CNTs, H₂O₂ will be oxidized or reduced at large overpotentials, with a large potential region between these two processes where electrochemical activity is negligible. At N-CNTs, the overpotential for both H₂O₂ oxidation and reduction is significantly reduced; however, the reduction current from H₂O₂, especially at low overpotentials, is attributed to increased oxygen reduction rather than the direct reduction of H₂O₂, due to a fast chemical disproportionation of H₂O₂ at the N-CNT surface. Additionally, N-CNTs do not display separation between observable oxidation and reduction currents from H₂O₂. Overall, the analytical sensitivity of N-CNTs to H₂O₂, either by oxidation or reduction, is considerably higher than CNTs, and obtained at significantly lower overpotentials. N-CNTs display an anodic sensitivity and limit of detection of 830 mA M^–1 cm^–2 and 0.5 μM at 0.05 V, and a cathodic sensitivity and limit of detection of 270 mA M^–1 cm^–2 and 10 μM at −0.25 V (V vs Hg/Hg₂SO₄). N-CNTs are also a superior platform for the creation of bioelectrodes from the spontaneous adsorption of enzyme, compared to CNTs. Glucose oxidase (GOx) was allowed to adsorb onto N-CNTs, producing a bioelectrode with a sensitivity and limit of detection to glucose of 80 mA M^–1 cm^–2 and 7 μM after only 30 s of adsorption time from a 81.3 μM GOx solution

América Latina. Los derechos y las prácticas ciudadanas a la luz de los movimientos populares

A partir, fundamentalmente, de los análisis de caso y los datos que ha sistematizado el Observatorio Social de América Latina (OSAL), nuestra propuesta gira en torno a dos preguntas centrales: ¿qué características presenta la noción de ciudadanía en las luchas sociales latinoamericanas recientes?, y ¿qué importancia adquiere dicha dimensión para la consecución de un propósito democrático? Buscando responder ambas, hemos dividido la exposición en tres apartados. En el primero se exploran los elementos que han favorecido el reposicionamiento de la noción de ciudadanía, dentro del horizonte y discurso de las movilizaciones que a partir del año 2000 han aparecido en distintos puntos del subcontinente. En el segundo, se examinan las características más relevantes que desde nuestro punto de vista hilvanan su diversidad. Y, finalmente, en el último se desarrollan las razones por las cuales consideramos que la noción de ciudadanía ocupa un lugar estratégico en la lucha social latinoamericana de este inicio de milenio.Presentación | 9 Lucha social y derechos ciudadanos en América Latina Margarita Favela Gavia y Diana Guillén | 21 Conflictos y tensiones en torno del Estado ampliado en América Latina: Brasil y México entre la crisis orgánica del Estado y el problema de la hegemonía Lucio Oliver | 51 Movimiento-partido: el caso del Movimiento de los Trabajadores sin Tierra (MST) en Brasil Adelita Neto Carleial | 81 Seguridad alimentaria y diseño de nuevos espacios públicos en Brasil Elza Maria Franco Braga | 111 Democracia y ciudadanía en el movimiento lopezobradorista Carlos Figueroa Ibarra y Octavio H. Moreno | 129 Venciendo el miedo: retoños de movimientos sociales en el contexto de la recuperación democrática en Perú (2000-2006) Fabiola Escárzaga | 155 Reflexiones sobre la democracia y el significado de un gobierno de los movimientos sociales en Bolivia Dunia Mokrani Chávez | 191 Entre la izquierda partidista y la izquierda social: el movimiento étnico maya y las opciones político-partidistas en Guatemala Luis Fernando Mack, Máximo Ba Tiul e Ivonne Solórzano | 215 Movimiento social y proceso político en Haití (1986-2006) Alejandro Álvarez Martínez | 24

Chitosan-G-Glycidyl Methacrylate/Au Nanocomposites Promote Accelerated Skin Wound Healing

Herein, we report the synthesis of Au nanoparticles (AuNPs) in chitosan (CTS) solution by chemically reducing HAuCl4. CTS was further functionalized with glycidyl methacrylate (chitosan-g-glycidyl methacrylate/AuNP, CTS-g-GMA/AuNP) to improve the mechanical properties for cellular regeneration requirements of CTS-g-GMA/AuNP. Our nanocomposites promote excellent cellular viability and have a positive effect on cytokine regulation in the inflammatory and anti-inflammatory response of skin cells. After 40 days of nanocomposite exposure to a skin wound, we showed that our films have a greater skin wound healing capacity than a commercial film (TheraForm®), and the presence of the collagen allows better cosmetic ave aspects in skin regeneration in comparison with a nanocomposite with an absence of this protein. Electrical percolation phenomena in such nanocomposites were used as guiding tools for the best nanocomposite performance. Our results suggest that chitosan-based Au nanocomposites show great potential for skin wound repair

Habitabilidad y política de vivienda

En esta obra, en la que participan destacados investigadores y profesores, dedicados al estudio de la problemática habitacional se presentan diferentes análisis que permiten conocer cuales son las condiciones de habitabilidad y las características de la actual política de vivienda de México. En sus capítulos se abordan los principales desafíos que enfrentan las familias mexicanas para acceder a una vivienda digna y decorosa y cuales son los retos económicos, políticos, territoriales, arquitectónicos, ambientales, financieros y culturales de las formas de producción habitacional en México y en otros países, en el marco de una sociedad global