Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 3 de 3
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
J Hazard Mater ; 275: 31-6, 2014 Jun 30.
Artículo en Inglés | MEDLINE | ID: mdl-24837462

RESUMEN

About 400,000 premature adult deaths attributable to air pollution occur each year in the European Region. Road transport emissions account for a significant share of this burden. While important technological improvements have been made for reducing particulate matter (PM) emissions from motor exhausts, no actions are currently in place to reduce the non-exhaust part of emissions such as those from brake wear, road wear, tyre wear and road dust resuspension. These "non-exhaust" sources contribute easily as much and often more than the tailpipe exhaust to the ambient air PM concentrations in cities, and their relative contribution to ambient PM is destined to increase in the future, posing obvious research and policy challenges. This review highlights the major and more recent research findings in four complementary fields of research and seeks to identify the current gaps in research and policy with regard to non-exhaust emissions. The objective of this article is to encourage and direct future research towards an improved understanding on the relationship between emissions, concentrations, exposure and health impact and on the effectiveness of potential remediation measures in the urban environment.


Asunto(s)
Contaminantes Atmosféricos/análisis , Vehículos a Motor , Contaminantes Atmosféricos/toxicidad , Contaminación del Aire/análisis , Contaminación del Aire/prevención & control , Ciudades , Polvo/análisis , Polvo/prevención & control , Monitoreo del Ambiente , Humanos , Modelos Teóricos
2.
Ultramicroscopy ; 110(4): 320-4, 2010 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-20149539

RESUMEN

Interactions between hairs and other natural fibers are of broad interest for both applications and fundamental understanding of biological interfaces. We present a novel method, that allows force measurements between individual hair strands. Hair fragments can be laser-cut without altering their surface chemistry. Subsequently, they are glued onto Atomic force microscopy (AFM) cantilevers. This allows carrying out measurements between the hair fragment and surface immobilized hair in a well-defined crossed-cylinder geometry. Both force-distance and friction measurements are feasible. Measurements in air with controlled humidity and in aqueous environment show clear differences which can be explained by the dominating role of capillary interactions in air. Friction is found to be anisotropic, reflecting the fine structure of hair cuticula. While the investigations are focused on the particular example of human hair, we expect that the approach can be extended to other animal/plant fibers and thus offers perspectives for broad spectrum systems.


Asunto(s)
Cabello/química , Cabello/ultraestructura , Microscopía de Fuerza Atómica/métodos , Preparaciones para el Cabello/análisis , Humanos , Humedad , Propiedades de Superficie
3.
Biochemistry ; 42(34): 10288-94, 2003 Sep 02.
Artículo en Inglés | MEDLINE | ID: mdl-12939158

RESUMEN

We report a kinetic and thermodynamic analysis of interactions between ssDNA and replication protein A (RPA) using surface plasmon resonance (SPR) and fluorescence correlation spectroscopy (FCS) at variable temperature. The two methods yield different values for the Gibbs free energy but nearly the same value for the reaction enthalpy of ssDNA-RPA complex formation. The Gibbs free energy was determined by SPR and FCS to be -62.6 and -54.7 kJ/mol, respectively. The values for the reaction enthalpy are -64.4 and -66.5 kJ/mol. It is concluded that the difference in Gibbs free energy measured by the two methods is due to different reaction entropies. The entropic contribution to the free energy at 25 degrees C is -1.8 kJ/mol for SPR and -11.8 kJ/mol for FCS. In SPR, the reaction is restricted to two dimensions because of immobilization of the DNA molecules to the sensor surface. In contrast, FCS is able to follow complex formation without spatial restrictions. In consequence, the reaction entropy determined from SPR experiments is lower than for FCS experiments.


Asunto(s)
ADN de Cadena Simple/metabolismo , Proteínas de Unión al ADN/metabolismo , ADN de Cadena Simple/química , Proteínas de Unión al ADN/química , Difusión , Relación Dosis-Respuesta a Droga , Proteínas de Escherichia coli/química , Proteínas de Escherichia coli/metabolismo , Cinética , Proteína de Replicación A , Espectrometría de Fluorescencia/métodos , Resonancia por Plasmón de Superficie , Temperatura , Termodinámica
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...