215 research outputs found
Arteriolopatía calcificante urémica, reporte de un caso tratado con tiosulfato de sodio
We describe a case of calcific uremic arteriolopathyinitially associated with skin lesions within the context of a patient with chronic kidney disease on automated peritoneal dialysis therapy. Among the most relevant findings, the patient hadhyperphosphatemia, normocalcemia and severe hyperparathyroidism without nodular hyperplasia. Clinical improvement with multimodal management of enhancement in dialysis therapy and intravenous sodium thiosulfate is highlighted. Calciphylaxis is a disorder that has a high morbidity and mortality, secondary to sepsis. It occurs more frequently in patients with chronic renal failure who are on hemodialysis. It is characterized by systemic medial calcification of the arterioles, triggering ischemia and subcutaneous necrosis of skin and soft tissues. Histopathological evaluation helps to confirm the diagnosis.Describimos un caso de arteriolopatía calcificante urémica asociada, inicialmente, a lesiones cutáneas,en unpaciente con insuficiencia renal crónica, en terapia de diálisis peritoneal automatizada, como hallazgos másrelevantes presentaba hiperfosfatemia, normocalcemia e hiperparatiroidismo severo sin hiperplasia nodular.Se destaca la mejoría clínica con manejo multimodal de intensificación en la terapia dialítica y tiosulfato desodio intravenoso.La calcifilaxis es un trastorno que debuta con alta morbilidad ymortalidad, secundaria a sepsis, ocurre con mayor frecuencia en pacientes con insuficiencia renal crónica que se encuentran en hemodiálisis. Se caracteriza por calcificación sistémica en la media de las arteriolas, desencadenándose isquemia y necrosis subcutánea de piel y tejidos blandos. La evaluación histopatológica ayuda a confirmar el diagnóstico
Solid particles formation from solutions, an intellectual and industrial meeting point and challenge
En aquest article presentem un recull d'experiències i idees sobre el problema de la formació de partícules sòlides nanomètriques i micromètriques a partir d'una solució. Presentem l'estat de la qüestió, alguns avanços en tècniques de precipitació, una descripció dels mecanismes de formació de partícules a partir d'una solució, amb una anàlisi de la influència de l'energia superficial formada en el curs de la nucleació sobre el procés d'agregació de nuclis. Es presenta un model d'agregació de partícules basat en la influència de les impureses.In this paper we will attempt to summarize a number of experiences and ideas concerning the problem of the formation of nanometric and micrometric solid particles from solutions. We will present the scope of the problem, some new advanced in techniques to produce and control the formation of solid particles, a description of a number of formation mechanisms of particles from solution, together with an analysis of the influence of the surface energy created in the nucleation process on the aggregation behavior of the nuclei formed. A new heuristic model on the aggregation mechanisms of particles, based on the action of impurities is proposed
Formation Mechanism of Maghemite Nanoflowers Synthesized by a Polyol-Mediated Process
Magnetic nanoparticles are being
developed as structural and functional
materials for use in diverse areas, including biomedical applications.
Here, we report the synthesis of maghemite (γ-Fe<sub>2</sub>O<sub>3</sub>) nanoparticles with distinct morphologies: single-core
and multicore, including hollow spheres and nanoflowers, prepared
by the polyol process. We have used sodium acetate to control the
nucleation and assembly process to obtain the different particle morphologies.
Moreover, from samples obtained at different time steps during the
synthesis, we have elucidated the formation mechanism of the nanoflowers:
the initial phases of the reaction present a lepidocrocite (γ-FeOOH)
structure, which suffers a fast dehydroxylation, transforming to an
intermediate “undescribed” phase, possibly a partly
dehydroxylated lepidocrocite, which after some incubation time evolves
to maghemite nanoflowers. Once the nanoflowers have been formed, a
crystallization process takes place, where the γ-Fe<sub>2</sub>O<sub>3</sub> crystallites within the nanoflowers grow in size (from
∼11 to 23 nm), but the particle size of the flower remains
essentially unchanged (∼60 nm). Samples with different morphologies
were coated with citric acid and their heating capacity in an alternating
magnetic field was evaluated. We observe that nanoflowers with large
cores (23 nm, controlled by annealing) densely packed (tuned by low
NaAc concentration) offer 5 times enhanced heating capacity compared
to that of the nanoflowers with smaller core sizes (15 nm), 4 times
enhanced heating effect compared to that of the hollow spheres, and
1.5 times enhanced heating effect compared to that of single-core
nanoparticles (36 nm) used in this work
Biology, incidence and host susceptibility of Pineus boerneri (Hemiptera : Adelgidae) in Colombian pine plantations
Adelgids (Hemiptera) in the genus Pineus have been reported as introduced insect
pests causing serious losses to Pinus plantations worldwide. In 2008, Pineus
boerneri was recorded for the first time in Colombia, with infestations noted on
Pinus kesiya, P. tecunumanii, P. maximinoi and P. oocarpa. The lack of information
on this insect in Colombia prompted investigations of its life cycle and infestation
levels as well as host susceptibility of the main Pinus species planted in Colombia.
In addition, the possibility of using a Ceraeochrysa species, an already established
predator of adelgids in Colombia for biological control, was considered. Results
showed that P. boerneri in Colombia has an anholocyclic life cycle comprised of
four instars with a complete duration between 49 and 97 days. Infestations were higher in the middle and upper part of trees. Pinus kesiya and P. maximinoi had
the highest levels of susceptibility in field as well as in greenhouse trials. A survey
of naturally infested trees showed P. tecunumanii to be moderately susceptible
while P. patula and P. oocarpa had low levels of susceptibility in a greenhouse trial
but were not susceptible in the field. Investigations considering the impact of
predation of Ceraeochrysa species showed a high predation rate of up to 140 P.
boerneri consumed per day by a single Ceraeochrysa individual. Other predators
of P. boerneri were recorded but were not sufficiently common to warrant detailed
study.Smurfit Kappa Cartón de Colombia and the National Research Foundation (NRF) of South Africa.http://www.tandfonline.com/loi/tsfs20hb201
Formation of the University Faculty in Methodological Stategies to Incorporation of E-Learning in European Space of Higher Education
El documento que presentamos, es una síntesis de una propuesta que presentamos al Ministerio
de Educación español, y se acoge a la línea de trabajo sobre «el proceso de aprendizaje
en el marco del EEES: estrategias universitarias», centrándonos más concretamente en el
desarrollo de nuevas metodologías docentes y del evaluación del aprendizaje así como en el análisis y creación de estrategias para la docencia universitaria orientadas al desarrollo
del aprendizaje electrónico.The document that present, is a synthesis of a proposal that present to Department of Spanish
Education, and is received to the line of work on the «process of learning in Europe Space
for Higher Education: university strategies», centering us more concretely in the development educational of new methodologies and of the evaluation of the learning as well as in the analysis and creation of strategies for the university teaching oriented toward development of the electronic learning
Estudio físico, químico y microestructural de geopolímeros base ceniza volante
En este trabajo se analizó el comportamiento físico, químico y microestructural de la ceniza volante
activada alcalinamente. Para ello fueron utilizados diferentes tamaños de partícula de ceniza
volante (CV), obtenidos por molienda manual, mezcladas con NaOH y curadas durante 7, 14 y 28
días. Las técnicas de caracterización utilizadas fueron: TGA, FTIR, MEB, adsorción física de gases
y pruebas de resistencia a compresión, además del software NIVision Assistant.
Los resultados muestran que la disminución de tamaño de partículas, favoreció la
geopolimerización del gel N-A-S-H y mejoró las propiedades cementantes en los geopolímeros,
logrando resistencias a compresión hasta de 23 MPa, por otro lado, se indica mediante análisis de
imagen, que los porcentajes de porosidad en cada uno de los morteros evaluados disminuyen
conforme se alejan de la zona de transición interfacial (ZTI), los cuales se corroboran con los
resultados de porosimetría.
(ANGLÈS)
In this paper was analyzed the physical, chemical and microstructural behavior of alkali activated
fly ash. This comparison was used with different particle sizes of fly ash (CV), obtained by manual
milling, mixed with NaOH and cured for 7, 14 and 28 days. The characterization techniques used:
TGA, FTIR, SEM, physical adsorption of gases and compressive strength tests, as well NIVision
Assistant software.
The results show that decreasing particle size favored NASH gel Geopolymerization and improved
cementitious properties in geopolymer, achieving compressive strengths up to 23 MPa. On the
other hand, indicated by image analysis, the percentages of porosity in each of the mortars
evaluated decrease as they move away from the interfacial transition zone (ZTI), these results are
corroborated by porosimetry method.Peer ReviewedPostprint (published version
Regeneración de campus para la creación de un laboratorio vivo de sostenibilidad ("living lab") en el Campus de Excelencia Internacional de Moncloa
La Universidad Politécnica de Madrid (UPM) a través de su Centro de Innovación en Tecnología para el Desarrollo Humano (itdUPM) está propiciando la generación de conciencia, conocimiento y soluciones innovadoras que contribuyen al cumplimiento de los Objetivos de Desarrollo Sostenible a través de un edificio que sirve como laboratorio de prueba para nuevas tecnologías verdes y como plataforma de ideación colaborativa y activación social
Radar on RAIA: High frequency radars in the RAIA Observatory
The RADAR ON RAIA project aims to update and extend beyond the Galician border the High Frequency (HF) radar network that has been operating since 2011 in the framework of the RAIA Observatory. The Project is allowing the establishment of a cross-border collaboration beyond the physical infrastructure itself, developing a sharing strategy of maintenance procedures, validation and data processing on both sides of the border, as well as an easy and public access to all the information. In addition, new products are being developed to exploit the potential of the HF radar technology.Peer Reviewe
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