Search results for "Critical"
showing 10 items of 3024 documents
Dianthus superbus as a critically endangered species in Latvia: evaluation of its growth conditions and conservation possibilities
2021
Abstract Dianthus superbus is one of the most endangered species in Latvia and is on the verge of local extinction. Therefore, the aim of this study was to inventory previously identified populations of D. superbus in Latvia and to develop activities to conserve this species in accordance with the results obtained in situ. Expeditions on 18 previously documented locations, according to the data of Nature Conservation Agency, revealed only three existing D. superbus localities in Latvia with a significant number of specimens located in the Latgale region near Silenieki. In 2020, for the first time, two more new D. superbus localities were found in the vicinity of these three approved locatio…
Tratamiento crítico de la información de estudiantes universitarios desde los entornos personales de aprendizaje
2019
Resumen Partiendo del Proyecto CAPPLE (financiado por el Ministerio español de Economía y Competitividad), en este artículo identificamos las estrategias y las herramientas en red utilizadas por 2054 estudiantes universitarios españoles de último curso para efectuar un tratamiento crítico de la información y gestionar su proceso de aprendizaje. Desde un diseño de investigación no experimental de tipo exploratorio, se ha utilizado un cuestionario validado a través de un triple procedimiento (juicio de expertos, entrevistas cognitivas y estudio piloto) para recoger datos de 75 universidades en España. Los resultados muestran que los futuros profesionales son conscientes de la necesidad de con…
Submicellar and micellar reversed-phase liquid chromatographic modes applied to the separation of beta-blockers.
2009
The behaviour of a reversed-phase liquid chromatographic (RPLC) system (i.e. elution order, resolution and analysis time), used in the analysis of β-blockers with acetonitrile-water mobile phases, changes drastically upon addition of an anionic surfactant (sodium dodecyl sulphate, SDS). Surfactant monomers cover the alkyl-bonded phase in different extent depending on the concentration of both modifiers, in the ranges 1 × 10-3-0.15 M SDS and 5-50% acetonitrile. Meanwhile, the surfactant is dissolved in the mobile phase as free monomers, associated in small clusters or forming micelles. Four characteristic RPLC modes are yielded, with transition regions between them: hydro-organic, micellar, …
Co-colonization with carbapenem-resistant Klebsiella pneumoniae and Acinetobacter baumannii in intensive care unit patients
2013
Objectives: This investigation was conducted to study co-colonization by carbapenem-resistant Klebsiella pneumoniae carbapenemase-producing K. pneumoniae (KPC-Kp) and Acinetobacter baumannii (CRAB) in intensive care unit (ICU) patients in Palermo, Sicily, a geographic area where both organisms are endemic in the healthcare setting. Risk factors at admission and during ICU stay and outcomes were also evaluated. Methods: All patients colonized by KPC-Kp, or CRAB, or both in 2 ICUs of a large general hospital during the period October 2011 – March 2012 were enrolled. Demographics and clinical data were collected. Resistance determinants and clonality of the 2 organisms were characterized by mo…
Acoustic monitoring of the artificial airway — experimental results
1997
Non-invasive acoustic airway-monitoring was evaluated in an experimental study. Recording amplitude and travel time of acoustic pulse response, an acoustic pattern of airway's geometry was then calculated. Measurements on models and excised human cadaver lungs were performed to discover whether displacement or obstruction of the artificial airway could be detected by its acoustic equivalent. Regression analysis revealed a close correlation between displacement of tracheostomy tubes and the shifting of the acoustic area-distance function (corr. coeff.: 0.97-1) and an adequate correlation between acoustic and planimetrical determination of cross-sectional area within the tubes (corr. coeff.: …
Double Thermoresponsive Block Copolymers Featuring a Biotin End Group
2010
A poly(oligo(ethylene glycol) monomethyl ether methacrylate)-block-poly(N-isopropyl methacrylamide) (POEGMA-b-PNIPMAM) block copolymer with a biotin end group on the PNIPMAM block as a biotarget was synthesized as a model system for temperature-controlled polymer immobilization. The synthesis was based on RAFT polymerization followed by postpolymerization modification of an activated ester precursor block and an exchange of the dithioester end group within one step. NMR, differential scanning calorimetry (DSC), dynamic light scattering (DLS), and turbidimetry measurements were performed to investigate the stimulus-responsive properties. The double thermoresponsive POEGMA-b-PNIPMAM with biot…
Controlled synthesis of poly(acetone oxime acrylate) as a new reactive polymer: Stimuli-responsive reactive copolymers
2007
Abstract Acetone oxime acrylate has been synthesized as a new active ester monomer. Free radical polymerization yielded a reactive polymer soluble in various organic solvents, such as chloroform, dioxane, DMSO, acetone, methanol, dichloromethane, DMF, and ethanol. Controlled radical polymerization of acetone oxime acrylate was successfully conducted using the RAFT, NMP and Iniferter method. Partly polymer analogous reaction with N-isopropylamine resulted in the reactive copolymer poly(N-isopropylacrylamide-co-acetone oxime acrylate), which featured a lower critical solution temperature (LCST) of 61 °C in water. Further, the reactivity of the copolymer was exemplary proven by complete reacti…
Design of nonionic surfactants for supercritical carbon dioxide
1996
Interfacially active block copolymer amphiphiles have been synthesized and their self-assembly into micelles in supercritical carbon dioxide (CO 2 ) has been demonstrated with small-angle neutron scattering (SANS). These materials establish the design criteria for molecularly engineered surfactants that can stabilize and disperse otherwise insoluble matter into a CO 2 continuous phase. Polystyrene- b -poly(1,1-dihydroperfluorooctyl acrylate) copolymers self-assembled into polydisperse core-shell-type micelles as a result of the disparate solubility characteristics of the different block segments in CO 2 . These nonionic surfactants for CO 2 were shown by SANS to be capable of emulsifying u…
Contra la patologización intensiva en términos de derechos humanos: Activismo gordo en Argentina
2020
This work addresses the way in which Argentine Fat Activism has developed, in recent years, the demand for depathologization of fatness, taking elements from critical discourses on the health of fat people to frame them in a perspective typical of the Human Rights. First, the contemporary fat body is described in terms of stigma and discrimination, especially in the health field. Then, they refer to a series of critical positions on the pathologization and medicalization of fatness from the biomedical perspective, Fat Studies and Fat Activism. Lastly, a series of interventions that the Argentine activist collective Taller Hacer la Vista Gorda produced between 2017 and 2020 were considered, …
Thermodynamic properties of a liquid–vapor interface in a two-component system
2010
Abstract We report a complete set of thermodynamic properties of the interface layer between liquid and vapor two-component mixtures, using molecular dynamics. The mixtures consist of particles which have identical masses and diameters and interact with a long-range Lennard-Jones spline potential. The potential depths in dimensionless units for like interactions is 1 (for component 1) and 0.8 (for component 2). The surface excess entropy decreases when the temperature increases, so the surface has a negative excess heat capacity. This is a consequence of the fact that the surface tension decreases to zero at the critical point, proportional to ( T C , i − T ) 2 ν . The surface entropy decre…