Video Experimental Relacionado
Updated: Jul 12, 2026
05:56
Spot Variation Fluorescence Correlation Spectroscopy for Analysis of Molecular Diffusion at the Plasma Membrane of Living Cells
Published on: November 12, 2020
Evidencia observacional para una posible nueva vía de difusión
Science (New York, N.Y.)
|January 4, 1991
Resumen
Una nueva investigación revela que los tubos intracristalinos submicroscópicos son una nueva vía de difusión en anfibolitos deformados. Estas nuevas vías, observadas a través de la microscopía electrónica de transmisión, facilitan un transporte de material más rápido que los procesos geológicos previamente conocidos.
Área de la Ciencia:
- Geología Geología Geología.
- Ciencia de los materiales Ciencia de los materiales.
- La geoquímica es la geoquímica.
Sus antecedentes:
- Los tubos intracristalinos submicroscópicos no han sido previamente reconocidos como vías de difusión.
- Los defectos lineales en los minerales pueden exhibir un contraste y un comportamiento inusuales bajo la irradiación de electrones.
Objetivo del estudio:
- Para investigar la naturaleza de los defectos lineales en anfibolitos experimentalmente deformados.
- Para determinar si estos defectos representan un nuevo tipo de vía de difusión.
Principales métodos:
- La microscopía electrónica de transmisión (TEM, por sus siglas en inglés) se utilizó para examinar anfibolitos experimentalmente deformados.
- Se analizaron minerales como plagioclasa y anfibol para detectar defectos lineales y su comportamiento bajo irradiación electrónica.
Principales resultados:
- Los cristales de plagioclase y anfibol deformados mostraron defectos lineales que se asemejan a dislocaciones de la unidad con un contraste inusual.
- La irradiación de electrones hizo que estos defectos se expandieran en tubos vidriosos bien definidos de aproximadamente 20 nanómetros de diámetro.
- Estos tubos parecen haber sido llenados con líquido silicato-agua durante experimentos.
Conclusiones:
- Los tubos intracristalinos submicroscópicos alrededor de defectos lineales son una vía de difusión no reconocida anteriormente.
- El transporte a través de estos tubos es potencialmente órdenes de magnitud más rápido que los mecanismos de difusión tradicionales.
- Este hallazgo tiene implicaciones significativas para la comprensión del transporte de materiales en entornos geológicos.
Videos de Conceptos Relacionados
01:12Diffusion
Diffusion is the passive movement of substances down their concentration gradients—requiring no expenditure of cellular energy. Substances, such as molecules or ions, diffuse from an area of high concentration to an area of low concentration in the cytosol or across membranes. Eventually, the concentration will even out, with the substance moving randomly but causing no net change in concentration. Such a state is called dynamic equilibrium, which is essential for maintaining overall...
01:21Diffusion
Diffusion is a type of passive transport. In passive transport, a substance tends to move from an area of high concentration to an area of low concentration until the concentration is equal across the space. For example, take the diffusion of substances through the air. When someone opens a perfume bottle in a room filled with people, the perfume is at its highest concentration in the bottle and is at its lowest at the edges of the room. The perfume vapor will diffuse, or spread away, from the...
01:17Passive Diffusion: Overview and Kinetics
Passive diffusion is a critical process that allows small lipophilic drugs to cross the cell membrane along a concentration gradient. This mechanism's efficiency depends on four primary factors: the membrane's surface area, the drug's lipid-water partition coefficient, the concentration gradient, and the membrane's thickness.
When administered orally, drugs establish a substantial concentration gradient between the gastrointestinal (GI) lumen and the bloodstream, expediting their diffusion into...
When administered orally, drugs establish a substantial concentration gradient between the gastrointestinal (GI) lumen and the bloodstream, expediting their diffusion into...
01:15Theories of Dissolution: Diffusion Layer Model
Dissolution, the process by which drug particles dissolve in a solvent, is explained by the diffusion layer model, a theoretical framework that simulates the absorption of oral drugs and allows us to analyze experimental data.
This process starts with a thin layer, saturated with the drug, forming at the interface between the solid and liquid. The solute then diffuses from this layer into the main solution. The Noyes-Whitney equation suggests that the rate of dissolution relies on the diffusion...
This process starts with a thin layer, saturated with the drug, forming at the interface between the solid and liquid. The solute then diffuses from this layer into the main solution. The Noyes-Whitney equation suggests that the rate of dissolution relies on the diffusion...
03:48Behavior of Gas Molecules: Molecular Diffusion, Mean Free Path, and Effusion
Although gaseous molecules travel at tremendous speeds (hundreds of meters per second), they collide with other gaseous molecules and travel in many different directions before reaching the desired target. At room temperature, a gaseous molecule will experience billions of collisions per second. The mean free path is the average distance a molecule travels between collisions. The mean free path increases with decreasing pressure; in general, the mean free path for a gaseous molecule will be...
01:24Protein Diffusion in the Membrane
Proteins show rotational as well as lateral diffusion across the membrane. The lateral diffusion of proteins was confirmed through the cell fusion experiment where mouse and human cells were fused, resulting in hybrid cells. When the human and mouse cells fused, the specific membrane proteins on human and mouse cells were marked with the red and green-fluorescent markers, respectively. Initially, the red and green fluorescence was located on the respective hemisphere of the cell. As time...