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
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 ...
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 ...
India's 'holy powder' finally reveals its centuries-old secret
Chemistry / Analytical Chemistry
Apr 20, 2009 |
4.7 / 5 (31) |
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Scientists in Michigan are reporting discovery of the secret behind the fabled healing power of the main ingredient in turmeric — a spice revered in India as "holy powder." Their study on the ingredient, curcumin, ...
Groundbreaking discovery may lead to stronger antibiotics
Biology /
Oct 01, 2008 |
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The last decade has seen a dramatic decline in the effectiveness of antibiotics, resulting in a mounting public health crisis across the world. A new breakthrough by University of Virginia researchers provides physicians ...
'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 ...
Molecular bridge serves as a tether for a cell's nucleus
Biology /
Aug 08, 2008 |
4.8 / 5 (14) |
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(PhysOrg.com) -- A cell's nucleus - home of it its most precious contents — is a delicate envelope that, without support, is barely able to withstand the forces that keep it in place. Now, researchers have ...
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 ...
Researchers identify mechanism that helps bacteria avoid destruction in cells
Oct 10, 2009 |
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Infectious diseases currently cause about one-third of all human deaths worldwide, more than all forms of cancer combined. Advances in cell biology and microbial genetics have greatly enhanced understanding of the cause and ...
Robo-bats with metal muscles may be next generation of remote control flyers
Jul 07, 2009 |
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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 ...
First reported video of cell's recognition of danger through its protein response
Biology /
Aug 13, 2008 |
4.7 / 5 (10) |
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(PhysOrg.com) -- Cells are expected to respond defensively when an antigen lands on a cell membrane and prepares to cause mischief.
Researchers demonstrate a flexible, 1-step assembly of nanoscale structures
Jul 25, 2008 |
4.4 / 5 (10) |
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Scientists at the University of Pennsylvania have created a one-step, repeatable method for the production of functional nanoscale patterns or motifs with adjustable features, size and shape using a single master "plate."
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 ...
Scientists watch membrane fission in real time
Dec 11, 2008 |
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Researchers at The Scripps Research Institute have solved one of biology's neatest little tricks: they have discovered how a cell's outer membrane pinches a little pouch from itself to bring molecules outside the cell inside—without ...
Chemists discover recipe to design a better type of fuel cell
Oct 18, 2009 |
3.9 / 5 (11) |
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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 ...
A sharper look at malaria
Sep 02, 2008 |
4.1 / 5 (10) |
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(PhysOrg.com) -- In work that could lead to new ways of detecting and treating malaria, MIT researchers have used two advanced microscopy techniques to show in unprecedented detail how the malaria parasite ...
