Membrane
hideA membrane is a layer of material which serves as a selective barrier between two phases and remains impermeable to specific particles, molecules, or substances when exposed to the action of a driving force. Some components are allowed passage by the membrane into a permeate stream, whereas others are retained by it and accumulate in the retentate stream.
Membranes can be of various thickness, with homogeneous or heterogeneous structure. Membrane can also be classified according to their pore diameter. According to IUPAC, there are three different types of pore size classifications: microporous (dp < 2nm), mesoporous (2nm < dp < 50nm) and macroporous (dp > 50nm). Membranes can be neutral or charged, and particles transport can be active or passive. The latter can be facilitated by pressure, concentration, chemical or electrical gradients of the membrane process. Membranes can be generally classified into three groups: inorganic, polymeric or biological membranes. These three types of membranes differ significantly in their structure and functionality.
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News tagged with membrane
Computational microscope peers into the working ribosome (w/ Video)
Nov 23, 2009 |
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Two new studies reveal in unprecedented detail how the ribosome interacts with other molecules to assemble new proteins and guide them toward their destination in biological cells. The studies used molecular ...
Chemists discover recipe to design a better type of fuel cell
Oct 18, 2009 |
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Fuel cells are often touted as one method to help decrease society's addiction to fossil fuels. But there is still a lot of work to be done before fuel cells will be ready for mass market to be used in transportation, home ...
Researchers identify new, cancer-causing role for protein
Aug 27, 2009 |
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The mainstay immune system protein TRAF6 plays an unexpected, key role activating a cell signaling molecule that in mutant form is associated with cancer growth, researchers at The University of Texas M. D. ...
Major insights into evolution of life reported
Aug 19, 2009 |
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(PhysOrg.com) -- Humans might not be walking the face of the Earth were it not for the ancient fusing of two prokaryotes -- tiny life forms that do not have a cellular nucleus. UCLA molecular biologist James ...
Breakthrough uses light to manipulate cell movement
Aug 19, 2009 |
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One of the biggest challenges in scientists' quest to develop new and better treatments for cancer is gaining a better understanding of how and why cancer spreads. Recent breakthroughs have uncovered how ...
Scientists manipulate ripples in graphene, enabling strain-based graphene electronics (w/ Video)
Nanotechnology / Nanomaterials
Jul 26, 2009 |
4.8 / 5 (13) |
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(PhysOrg.com) -- Graphene is nature's thinnest elastic material and displays exceptional mechanical and electronic properties. Its one-atom thickness, planar geometry, high current-carrying capacity and thermal ...
Implantable Device Offers Continuous Cancer Monitoring
Nanotechnology / Bio & Medicine
Jul 21, 2009 |
5 / 5 (3) |
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(PhysOrg.com) -- Surgical removal of a tissue sample is now the standard for diagnosing cancer. Such procedures, known as biopsies, are accurate but offer only a snapshot of the tumor at a single moment in time.
Robo-bats with metal muscles may be next generation of remote control flyers
Jul 07, 2009 |
4.5 / 5 (11) |
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Tiny flying machines can be used for everything from indoor surveillance to exploring collapsed buildings, but simply making smaller versions of planes and helicopters doesn't work very well. Instead, researchers ...
Structural biology scores with protein snapshot
Jun 25, 2009 |
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In a landmark technical achievement, investigators in the Vanderbilt Center for Structural Biology have used nuclear magnetic resonance (NMR) methods to determine the structure of the largest membrane-spanning ...
Membrane filters are key to future of public water supply, scientists say
Apr 21, 2009 |
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As municipalities across the United States reduce their dependence on groundwater sources to mitigate environmental impacts like subsidence and flooding, there is a growing need for better purification processes to keep contaminants ...
Alzheimer’s Findings Resolve Dispute Over How Disease Kills Brain Cells
Medicine & Health / Neuroscience
Apr 15, 2009 |
4.2 / 5 (6) |
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(PhysOrg.com) -- For a decade, Alzheimer's disease researchers have been entrenched in debate about one of the mechanisms believed to be responsible for brain cell death and memory loss in the illness.
'Holy powder' ingredient makes membranes behave for better health
Chemistry / Analytical Chemistry
Mar 06, 2009 |
4.9 / 5 (14) |
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Revered in India as "holy powder," the marigold-colored spice known as turmeric has been used for centuries to treat wounds, infections and other health problems. In recent years, research into the healing powers of turmeric's ...
How mosquitoes could teach us a trick in the fight against malaria
Mar 05, 2009 |
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(PhysOrg.com) -- The means by which most deadly malaria parasites are detected and killed by the mosquitoes that carry them is revealed for the first time in research published today in Science Express. The di ...
Buckyballs could keep water systems flowing
Nanotechnology / Bio & Medicine
Mar 05, 2009 |
3.6 / 5 (7) |
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Microscopic particles of carbon known as buckyballs may be able to keep the nation's water pipes clear in the same way clot-busting drugs prevent arteries from clogging up.
Scientists create world's thinnest balloon, just 1 atom thick
Sep 19, 2008 |
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(PhysOrg.com) -- Using a lump of graphite, a piece of Scotch tape and a silicon wafer, Cornell researchers have created a balloonlike membrane that is just one atom thick -- but strong enough to contain gases ...
