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Search Results: 1 - 10 of 268442 matches for " Diana Y. Escalante-Réndiz "
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Composting Used as a Low Cost Method for Pathogen Elimination in Sewage Sludge in Mérida, Mexico
Dulce Diana Caba?as-Vargas,Emilio. de los Ríos Ibarra,Juan. P. Mena-Salas,Diana Y. Escalante-Réndiz,Rafael Rojas-Herrera
Sustainability , 2013, DOI: 10.3390/su5073150
Abstract: Spreading sewage sludge from municipal wastewater (MWW) treatment on land is still a common practice in developing countries. However, it is well known that sewage sludge without special treatment contains various pollutants, which are (re)introduced into the environment by sludge landspreading and which might in turn have harmful effects on the environment and human health. This is more dangerous in places like Merida, Mexico, where soil is calcareous with fractures along the ground and thin layers of humus. Consequently, any liquid and semisolid wastes have the potential of percolating to the subsurface and contaminate the aquifer. The main aim of this work was using composting as a low cost process to eliminate pathogens contained in sewage sludge from MWW treatment in order to use the final product for land spreading in a safe way for both environment and human health. Two piles for composting process at real scale were settled using a mixture of sewage sludge from municipal waste water and green waste. Composting was carried out by windrow process and it was monitored during four weeks. Concentration of helminth eggs, salmonella and faecal coliforms were measured twice a week to observe its behavior and, as a control process, Temperature, Moisture Content (MC), and pH were also measured. After 30 days of composting sludge from municipal waste water system, salmonella was eliminated by 99%, faecal coliforms by 96% and helminth eggs by 81%. After 3 months compost reached GI = 160%, so did not show any phytotoxicity to seeds.
The Potential Economic Value of a Trypanosoma cruzi (Chagas Disease) Vaccine in Latin America
Bruce Y. Lee ,Kristina M. Bacon,Diana L. Connor,Alyssa M. Willig,Rachel R. Bailey
PLOS Neglected Tropical Diseases , 2010, DOI: 10.1371/journal.pntd.0000916
Abstract: Background Chagas disease, caused by the parasite Trypanosoma cruzi (T. cruzi), is the leading etiology of non-ischemic heart disease worldwide, with Latin America bearing the majority of the burden. This substantial burden and the limitations of current interventions have motivated efforts to develop a vaccine against T. cruzi. Methodology/Principal Findings We constructed a decision analytic Markov computer simulation model to assess the potential economic value of a T. cruzi vaccine in Latin America from the societal perspective. Each simulation run calculated the incremental cost-effectiveness ratio (ICER), or the cost per disability-adjusted life year (DALY) avoided, of vaccination. Sensitivity analyses evaluated the impact of varying key model parameters such as vaccine cost (range: $0.50–$200), vaccine efficacy (range: 25%–75%), the cost of acute-phase drug treatment (range: $10–$150 to account for variations in acute-phase treatment regimens), and risk of infection (range: 1%–20%). Additional analyses determined the incremental cost of vaccinating an individual and the cost per averted congestive heart failure case. Vaccination was considered highly cost-effective when the ICER was ≤1 times the GDP/capita, still cost-effective when the ICER was between 1 and 3 times the GDP/capita, and not cost-effective when the ICER was >3 times the GDP/capita. Our results showed vaccination to be very cost-effective and often economically dominant (i.e., saving costs as well providing health benefits) for a wide range of scenarios, e.g., even when risk of infection was as low as 1% and vaccine efficacy was as low as 25%. Vaccinating an individual could likely provide net cost savings that rise substantially as risk of infection or vaccine efficacy increase. Conclusions/Significance Results indicate that a T. cruzi vaccine could provide substantial economic benefit, depending on the cost of the vaccine, and support continued efforts to develop a human vaccine.
Insights into imaging of aortitis
Diana E. Litmanovich,Afra Y ld r m,Alexander A. Bankier
Insights into Imaging , 2012, DOI: 10.1007/s13244-012-0192-x
Abstract: Contrast-enhanced CT, MRI and PET-CT are used for both the initial diagnosis and follow-up of aortitis.
Morphometric differences in two calanoid sibling species, Boeckella gracilipes and B. titicacae (Crustacea, Copepoda)
Escalante, Patricio De los Ríos;
Iheringia. Série Zoologia , 2012, DOI: 10.1590/S0073-47212012000400013
Abstract: calanoid copepods are abundant in south american inland waters and include widespread species, such as boeckella gracilipes (daday, 1902), which occurs from the ecuador to tierra del fuego island. this species occurs under various environmental conditions, and is found in oligotrophic lakes in patagonia (39-54°s) and in shallow mountain lakes north of 39°s. the aim of the present study is to conduct a morphometric comparison of male specimens of b. titicacae collected in titicaca and b. gracilipes collected in ri?ihue lakes, with a third population of b. gracilipes collected in shallow ponds in salar de surire. titicaca and ri?ihue lakes are stable environments, whereas salar de surire is an extreme environment. these ponds present an extreme environment due to high exposure to solar radiation and high salinity levels. the results of the study revealed differences among the three populations. these results agree well with systematic descriptions in the literature on differences between the populations of titicaca and ri?ihue lakes, and population of salar de surire differs slightly from the other two populations. it is probable that the differences between the population of salar de surire and the other two populations result from the extreme environment in salar de surire. high exposure to solar radiation, high salinity and extreme variations in temperature enhance genetic variations that are consequently expressed in morphology.
Morphometric differences in two calanoid sibling species, Boeckella gracilipes and B. titicacae (Crustacea, Copepoda) Diferencias morfométricas en dos especies hermanas Boeckella gracilipes y Boeckella titicacae (Crustacea, Copepoda)
Patricio De los Ríos Escalante
Iheringia. Série Zoologia , 2012,
Abstract: Calanoid copepods are abundant in South American inland waters and include widespread species, such as Boeckella gracilipes (Daday, 1902), which occurs from the Ecuador to Tierra del Fuego Island. This species occurs under various environmental conditions, and is found in oligotrophic lakes in Patagonia (39-54°S) and in shallow mountain lakes north of 39°S. The aim of the present study is to conduct a morphometric comparison of male specimens of B. titicacae collected in Titicaca and B. gracilipes collected in Ri ihue lakes, with a third population of B. gracilipes collected in shallow ponds in Salar de Surire. Titicaca and Ri ihue lakes are stable environments, whereas Salar de Surire is an extreme environment. These ponds present an extreme environment due to high exposure to solar radiation and high salinity levels. The results of the study revealed differences among the three populations. These results agree well with systematic descriptions in the literature on differences between the populations of Titicaca and Ri ihue lakes, and population of Salar de Surire differs slightly from the other two populations. It is probable that the differences between the population of Salar de Surire and the other two populations result from the extreme environment in Salar de Surire. High exposure to solar radiation, high salinity and extreme variations in temperature enhance genetic variations that are consequently expressed in morphology. Los copépodos calanoideos son abundantes en aguas continentales sudamericanas e incluyen especies de amplia distribución geográfica como Boeckella gracilipes (Daday, 1902) que se encuentra desde Ecuador hasta la isla de Tierra del Fuego. Esta especie vive bajo varias condiciones ambientales, y se encuentra en lagos oligotróficos en la Patagonia (39-54°S) y en lagunas superficiales de monta a al norte de los 39°S. El objetivo del presente trabajo es realizar un estudio comparativo morfométrico de machos de B. titicacae colectado en el lago Titicaca y B. gracilipes colectado en el lago Ri ihue, ambos son ambientes estables, con una tercera población colectada en lagunas superficiales en el Salar de Surire. Estas lagunas tienen condiciones ambientales extremas debido a alta exposición a la radiación solar y altos niveles de salinidad. Los resultados del presente estudio encontraron diferencias entre las tres poblaciones. Estos resultados concordarían con las descripciones sistemáticas en la literatura sobre las diferencias de las poblaciones de los lagos Titicaca y Ri ihue, y la población del salar de Surire tuvo leves diferencia
Inhibition of Striatal Soluble Guanylyl Cyclase-cGMP Signaling Reverses Basal Ganglia Dysfunction and Akinesia in Experimental Parkinsonism
Kuei Y. Tseng, Adriana Caballero, Alexander Dec, Daryn K. Cass, Natalie Simak, Elizabeth Sunu, Michael J. Park, Shannon R. Blume, Stephen Sammut, Diana J. Park, Anthony R. West
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0027187
Abstract: Objective There is clearly a necessity to identify novel non-dopaminergic mechanisms as new therapeutic targets for Parkinson's disease (PD). Among these, the soluble guanylyl cyclase (sGC)-cGMP signaling cascade is emerging as a promising candidate for second messenger-based therapies for the amelioration of PD symptoms. In the present study, we examined the utility of the selective sGC inhibitor 1H-[1], [2], [4] oxadiazolo-[4,3-a]quinoxalin-1-one (ODQ) for reversing basal ganglia dysfunction and akinesia in animal models of PD. Methods The utility of the selective sGC inhibitor ODQ for reversing biochemical, electrophysiological, histochemical, and behavioral correlates of experimental PD was performed in 6-OHDA-lesioned rats and mice chronically treated with MPTP. Results We found that one systemic administration of ODQ is sufficient to reverse the characteristic elevations in striatal cGMP levels, striatal output neuron activity, and metabolic activity in the subthalamic nucleus observed in 6-OHDA-lesioned rats. The latter outcome was reproduced after intrastriatal infusion of ODQ. Systemic administration of ODQ was also effective in improving deficits in forelimb akinesia induced by 6-OHDA and MPTP. Interpretation Pharmacological inhibition of the sGC-cGMP signaling pathway is a promising non-dopaminergic treatment strategy for restoring basal ganglia dysfunction and attenuating motor symptoms associated with PD.
Hydration and microstructure of Portland cement partially substituted with ultrafine silica
Gómez-Zamorano, L. Y.,Escalante, J. I.
Materiales de Construccion , 2009,
Abstract: Geothermal waste, a by-product of steam power plants that use geothermal underground resources, was studied as a possible replacement for Portland cement. This waste consists primarily in amorphous nanometric silica with traces of sodium and potassium chlorides. The replacement ratios studied were 0, 10 and 20% in cements cured at 20 and 60 oC. X-ray diffraction analysis showed that clinker phase hydration took place earlier in the presence of the geothermal waste. Scanning electron microscopy, in turn, revealed a reduction in porosity and intense calcium hydroxide consumption as a result of the pozzolanic reaction. The pastes containing 20% waste, however, an intense cracking was observed due to the formation of alkali silica reaction gel and ettringite. Cracking was more prominent at 60 oC but was not observed in either the neat cement or the blend with 10 % waste. The presence of these detrimental phases was attributed to the formation of Friedel’s salt in the initial hydration stages, induced by the chlorides in the geothermal material. Se investigaron pastas de cemento Portland sustituido con un desecho geotérmico, subproducto de la generación de electricidad en plantas que emplean recursos geotérmicos. El desecho está compuesto principalmente de sílice amorfa de tama o nanométrico, con cloruros de sodio y potasio. Se investigaron cementos con niveles de substitución de 0, 10 y 20%, curados a 20 y 60 °C. En presencia del desecho geotérmico, se observó por Difracción de rayos X cuantitativa que la hidratación de las fases del clínker se aceleró; además mediante microscopía electrónica de barrido se encontró una disminución en la porosidad y un intenso consumo de hidróxido de calcio por la reacción puzolánica. Sin embargo, para pastas con 20% de desecho geotérmico, se observó agrietamiento con la presencia de gel de reacción álcali sílice y ettringita; fue más acentuado a 60 °C y no se observó para pastas de cemento puro y con 10% de desecho. La presencia de las fases nocivas se atribuye a la formación de sal de Friedel en las etapas iniciales de hidratación, promovida por los cloruros provenientes del desecho geotérmico.
Band gaps and cavity modes in dual phononic and photonic strip waveguides
Y. Pennec,B. Djafari Rouhani,C. Li,J. M. Escalante
AIP Advances , 2011, DOI: 10.1063/1.3675799
Abstract: We discuss theoretically the simultaneous existence of phoxonic, i.e., dual phononic and photonic, band gaps in a periodic silicon strip waveguide. The unit-cell of this one-dimensional waveguide contains a hole in the middle and two symmetric stubs on the sides. Indeed, stubs and holes are respectively favorable for creating a phononic and a photonic band gap. Appropriate geometrical parameters allow us to obtain a complete phononic gap together with a photonic gap of a given polarization and symmetry. The insertion of a cavity inside the perfect structure provides simultaneous confinement of acoustic and optical waves suitable to enhance the phonon-photon interaction.
Skeletal Adaptation to Intramedullary Pressure-Induced Interstitial Fluid Flow Is Enhanced in Mice Subjected to Targeted Osteocyte Ablation
Ronald Y. Kwon, Diana R. Meays, Alexander S. Meilan, Jeremiah Jones, Rosa Miramontes, Natalie Kardos, Jiunn-Chern Yeh, John A. Frangos
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0033336
Abstract: Interstitial fluid flow (IFF) is a potent regulatory signal in bone. During mechanical loading, IFF is generated through two distinct mechanisms that result in spatially distinct flow profiles: poroelastic interactions within the lacunar-canalicular system, and intramedullary pressurization. While the former generates IFF primarily within the lacunar-canalicular network, the latter generates significant flow at the endosteal surface as well as within the tissue. This gives rise to the intriguing possibility that loading-induced IFF may differentially activate osteocytes or surface-residing cells depending on the generating mechanism, and that sensation of IFF generated via intramedullary pressurization may be mediated by a non-osteocytic bone cell population. To begin to explore this possibility, we used the Dmp1-HBEGF inducible osteocyte ablation mouse model and a microfluidic system for modulating intramedullary pressure (ImP) to assess whether structural adaptation to ImP-driven IFF is altered by partial osteocyte depletion. Canalicular convective velocities during pressurization were estimated through the use of fluorescence recovery after photobleaching and computational modeling. Following osteocyte ablation, transgenic mice exhibited severe losses in bone structure and altered responses to hindlimb suspension in a compartment-specific manner. In pressure-loaded limbs, transgenic mice displayed similar or significantly enhanced structural adaptation to Imp-driven IFF, particularly in the trabecular compartment, despite up to ~50% of trabecular lacunae being uninhabited following ablation. Interestingly, regression analysis revealed relative gains in bone structure in pressure-loaded limbs were correlated with reductions in bone structure in unpressurized control limbs, suggesting that adaptation to ImP-driven IFF was potentiated by increases in osteoclastic activity and/or reductions in osteoblastic activity incurred independently of pressure loading. Collectively, these studies indicate that structural adaptation to ImP-driven IFF can proceed unimpeded following a significant depletion in osteocytes, consistent with the potential existence of a non-osteocytic bone cell population that senses ImP-driven IFF independently and potentially parallel to osteocytic sensation of poroelasticity-derived IFF.
Freshwater ecosystems in oceanic islands of Chile: Conservation of endemic microfauna and the role of exotic species in the biological control of tropical diseases Ecosistemas acuáticos de islas oceánicas de Chile: Conservación de microfauna endémica y el rol de especies exóticas en el control biológico de enfermedades tropicales
PATRICIO R DE LOS RíOS-ESCALANTE
Revista chilena de historia natural , 2010,
Abstract:
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