This paper describes the preparation of a hydrophilic copolymer membrane with two comonomers: 1-vinyl-2-pyrrolidone (commercial) and a new water insoluble piperazinedione derivative, which is a ...fluorogenic mercury sensing motif. The dense membrane permitted the fluorogenic detection of Hg
2+ in aqueous media. The sensitivity of the membrane this cation was significantly high, with a detection limit of 10
ppt. This limit of detection is much lower than that of DMSO/water solutions of the sensing monomer, which is 10
ppb, and significantly lower than the maximum contaminant level (EPA) in drinking water, 2
ppb.
This work describes five novel aromatic polyamides and copolyamides containing the triazole heterocycle attached by an amine linkage to the main and lateral chains. The polyamides were found to be ...amorphous and soluble in polar aprotic solvents. They demonstrated a film-forming capability, exhibited good thermal resistance and had high thermal transition temperatures (up to 375 °C). The triazole and amine groups imparted hydrophilicity to the polymers, giving rise to materials that improve their mechanical properties upon water uptake, and were efficient chelating/host units for heavy metal cations. These properties facilitated the preparation of solid polymer phases to be used for the extraction and elimination of environmentally deleterious cations from water environments. In regards to cation extraction from aqueous media with polyamide solid phases, the correct polymer structure designs led to the extraction of high percentages of Hg
II
(neat 100%).
Novel aromatic polyamides with 1,2,4-triazole moieties and their application to the extraction/elimination of mercury cations from aqueous media.
Programmable electronic AC loads (PELs) are a new type of power electronic devices widely used by researches to emulate different load features, such as resistive, inductive, capacitive and ...non-linear loads. PELs are currently of great interest in the field of microgrid research, isolated or hybrid solar plants and power electronics device testing. This paper presents a review of PELs focusing on hardware topologies. Different hardware configurations are presented and discussed, explaining their functionality. One of the key issues regarding PELs design is the elimination of excessive active power drawn by the load. This can be performed by dissipating power in passive elements through DC-DC converters or re-injecting it into a receptive AC grid. Both options are explained and detailed in the paper.
'Retratos de calles vacías' es una apuesta de investigación-creación gestada a partir de un trabajo de reflexión y crítica social, enmarcado en la Maestría de Comunicación-Educación de la Universidad ...Francisco José de Caldas. El trabajo consiste en el análisis de la situación que diversos cuerpos enfrentaron durante la cuarentena estricta en Bogotá, debido a la propagación del Covid-19. La discusión se centra en el estudio del concepto 'cuerpo matable', el cual, involucra determinadas características que ponen ciertos cuerpos en mayores vulnerabilidades. Además, se ubica dentro de una ciudad vacía, donde el ejercicio del poder se materializa con el espaldarazo de un estado de excepción donde reina la incertidumbre y un estado de opinión donde domina el miedo y la cercanía con los otros. Para mitigar el fenómeno de 'cuerpo matable', se propone la creación de una serie de retratos audiovisuales, donde se cuenta la historia de Lucrecia, una mujer transgénero residente en Bogotá. Con la compañía de su voz, su cuerpo y su identidad, se conversa sobre la vida y la muerte, en una ciudad cada vez más tensa, donde ciertos cuerpos enfrentan obstáculos más complejos.
This paper describes a strategy followed to achieve a sensing phenomenon in aqueous media using water-insoluble organic molecules. We have prepared a methacrylamide and a methacrylate with pendant ...cyanide chemosensors based on a fluorene-derivative motif, and we have fabricated highly hydrophilic membranes by means of copolymerising these hydrophobic monomers with others. Therefore, upon absorption of water in the membranes, solvated ions enter the membrane by a simple diffusion mechanism, reaching the hydrophobic chemosensor motifs and giving rise to a macroscopic sensing phenomenon. In this way, we have prepared solid materials (dense membranes or films) capable of selectively detecting cyanide, with an extremely low detection threshold, in aqueous solution by means of colour changes (naked-eye sensing) (13 ppb). Nevertheless, the key point of this research is the description of the possibilities of anchoring organic insoluble molecules (
i.e.
, drugs, fungicides, bactericides, sensing probes,
etc.
) to solubilise them in water, or to prepare hydrogels, permitting the use of these molecules in aqueous media or in biological media for medical, biological or biochemical purposes.
This paper describes a strategy followed to achieve a sensing phenomenon in aqueous media using water-insoluble organic molecules. A sensory polymeric material for the colorimetric sensing of cyanide ...in water has been developed based on the reactivity of this anion with a fluorene derivative.
Sensory polymeric material (film strips) for the naked-eye colorimetric sensing of cyanide in water.
Sistemas de soporte hepático extracorpóreo Cadena, Fredy Ariza; Serna, Luis Felipe Carmona; Quintero C., Iván Fernando ...
Colombian journal of anesthesiology/Revista Colombiana de Anestesiología/Revista Colombiana de Anestesiologia,
11/2011, Letnik:
39, Številka:
4
Journal Article
Recenzirano
Odprti dostop
Los sistemas de soporte hepático extracorpóreo (SHE) surgen como una alternativa al trasplante hepático (TH), dado el incremento en la incidencia de falla hepática aguda (FHA), falla hepática crónica ...agudizada (FHCA), así como las restricciones en la oferta de órganos.
Revisión de la literatura de los sistemas de soporte hepático extracorporeo.
Búsqueda de la literatura publicada entre julio de 1990 y noviembre de 2010 en las principales bases de datos médicas que incluyeron MEDLINE, SciELO y EMBASE, de artículos que analizaran tecnologías relacionadas con sistemas de soporte hepático en cuanto a sus especificaciones técnicas, sus usos y la evidencia respecto a su efectividad en pacientes con algún tipo de falla hepática que requirieran soporte.
Estos sistemas pueden dividirse en artificiales (hemofiltración, sistema MARS) y bioartificiales (como el Hepatassist™). Su fundamento consiste en reemplazar los procesos de destoxificación relacionados específicamente con el sistema de bilirrubinas, la eliminación de aminoácidos aromáticos, agentes inflamatorios y el manejo de los productos de degradación del sistema de la coagulación. Los recientes avances en bioingeniería y biogenética han hecho que estas tecnologías se acerquen cada vez más a una forma ideal, permitiendo que sean utilizados con relativo éxito en humanos. Los SHE, en su gran mayoría en desarrollo, pretenden no solo actuar como puente al TH, sino que, en casos puntuales, pueden llegar a ser la piedra angular del tratamiento mientras la FHA logra resolverse.
Extracorporeal liver support systems (ELS) have emerged as an alternative to liver transplant (LT), given the growing incidence of acute liver failure (ALF), acute-on-chronic liver failure (ACLF) and the limited organ supply.
Review of literature about Extracorporeal Liver Support Systems.
A literature search was conducted on the main medical databases including MEDLINE, SciELO and EMBASE for papers published between July 1990 and November 2010 looking at technologies associated with liver support systems, their technical specifications, their use, and evidence regarding their effectiveness in patients with some forms of liver failure requiring support.
These systems may be divided into artificial (hemofiltration, MARS) and bioartificial (such as the Hepatassist™). They work by replacing detoxification processes associated specifically with bilirubins, aromatic aminoacids, and inflammatory agents, and the elimination of breakdown products of coagulation. Recent advances in bioengineering and biogenetics have brought these technologies closer to the ideal, enabling their use in humans with a relative degree of success. ELS systems, most of them still under development, are designed not only to act as a bridge for LT but may also become the cornerstone of treatment in specific cases while the ALF resolves.
This work describes six novel fluorescent aromatic polyamides with bulky dansyl or fluorene pendant groups or with the fluorene moiety in the main chain. The fluorescent signaling dansyl or fluorene ...moieties are chemically connected to, or within, the main polymer chains through a urea group, a well-known binding site in supramolecular chemistry. These polyamides are amorphous and soluble in polar aprotic solvents and demonstrate a film-forming capability. They also show yellowish-green or blue fluorescence in solution and in the solid state depending on the signaling unit, with the former corresponding to the dansyl and the latter to the fluorene residue. The water uptake and the thermal behavior have also been evaluated and related to the chemical structure. The polar amide, urea, and sulfonamide groups give rise to a high water sorption of up to 3.8 water molecules per repeating unit. The thermal behavior has been investigated by means of DSC and TGA. The glass transition temperatures of the polymers are high (up to 331
°C) and the decomposition temperatures (around 300
°C) are due to the moderate thermal stability of the urea group.
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