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Masdar's Beam Down Optical Tower : I wrote about Masdar city some time back. They now have an Optical Tower which works quietly efficiently and without any carbon emissions - The Beam Down Tower at Masdar is a step forward in concentrated solar power (CSP). Unlike other plants, the system reflects sunlight twice, once from the heliostats to the central tower and once from the tower down to a collection platform at the system’s base. Because scientists can focus the sunlight at a very small area, they can achieve great heat. They recently concentrated solar energy to 1,100 degrees. The plant is currently only 100 kW, but designers say it could scale up easily.
Thirty-three heliostats—mirrors arranged in the shape of a parabola—circle the 66-foot tower in three concentric rings. Motors adjust the elevation and angle of the heliostats throughout the day to track the sun.
An array of 45 mirrors made to reflect as much solar radiation as possible, also arranged in concentric circles, lines the underside of the central tower. Each ring corresponds to a specific ring of heliostats.
More on Masdar city (eco-city) - https://plus.google.com/u/0/110884604033336753419/posts/1HfDvjgZuh5
Article Link: http://www.popsci.com/science/article/2013-05/beam-down-optical-experiment
#science #scienceeveryday #greenenergy #solarenergy #solarpower #masdarcity #ecology #alternativeenergy
Thirty-three heliostats—mirrors arranged in the shape of a parabola—circle the 66-foot tower in three concentric rings. Motors adjust the elevation and angle of the heliostats throughout the day to track the sun.
An array of 45 mirrors made to reflect as much solar radiation as possible, also arranged in concentric circles, lines the underside of the central tower. Each ring corresponds to a specific ring of heliostats.
More on Masdar city (eco-city) - https://plus.google.com/u/0/110884604033336753419/posts/1HfDvjgZuh5
Article Link: http://www.popsci.com/science/article/2013-05/beam-down-optical-experiment
#science #scienceeveryday #greenenergy #solarenergy #solarpower #masdarcity #ecology #alternativeenergy
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Crucial and yet Controversial: WI-38 Cells
• Many people are aware of the history behind HeLa cells; isolated from Henrietta Lacks and used today in thousands of laboratories (http://goo.gl/eOPRW). But did you know about WI-38 cells? Isolated in June 1962 by Leonard Hayflick, these cells came from a legally aborted fetus in Sweden.
• Isolated at a time when the law did not require consent for the use of tissues in research, there is likely no recourse for the parents of the fetus or their heirs for compensation. Sigma Aldrich, a biotechnology company currently charges $424 for a vial of these cells.
• Unlike HeLa cells which are a cervical cancer cell line, the WI-38 cells are normal. These cells undergo a fixed number of cell divisions, usually 50 and then stop; a process known as cellular senescence.
• WI-38 cells were an invaluable tool to culture various human viruses for the manufacture of vaccines; rubella, rabies, adenovirus, polio, measles, chickenpox and shingles vaccines that have saved hundreds of millions of lives since.
• The controversy surrounding these cells still rages on today; because they are derived from an aborted fetus, many pro-life activists object to their use in research. Ironically, "the rubella vaccine, developed using WI-38 cells, has prevented thousands more abortions than have ever been prevented by Catholic religionists" according to Professor Stanley Plotkin, the researcher who developed the rubella vaccine.
• These cells have a fascinating history, and the full article is well worth a read: http://www.nature.com/news/medical-research-cell-division-1.13273#comments
Image: Some original glass ampoules of WI-38 cells, created in 1962. Copyright Leonard Hayflick.
#ScienceEveryday
• Many people are aware of the history behind HeLa cells; isolated from Henrietta Lacks and used today in thousands of laboratories (http://goo.gl/eOPRW). But did you know about WI-38 cells? Isolated in June 1962 by Leonard Hayflick, these cells came from a legally aborted fetus in Sweden.
• Isolated at a time when the law did not require consent for the use of tissues in research, there is likely no recourse for the parents of the fetus or their heirs for compensation. Sigma Aldrich, a biotechnology company currently charges $424 for a vial of these cells.
• Unlike HeLa cells which are a cervical cancer cell line, the WI-38 cells are normal. These cells undergo a fixed number of cell divisions, usually 50 and then stop; a process known as cellular senescence.
• WI-38 cells were an invaluable tool to culture various human viruses for the manufacture of vaccines; rubella, rabies, adenovirus, polio, measles, chickenpox and shingles vaccines that have saved hundreds of millions of lives since.
• The controversy surrounding these cells still rages on today; because they are derived from an aborted fetus, many pro-life activists object to their use in research. Ironically, "the rubella vaccine, developed using WI-38 cells, has prevented thousands more abortions than have ever been prevented by Catholic religionists" according to Professor Stanley Plotkin, the researcher who developed the rubella vaccine.
• These cells have a fascinating history, and the full article is well worth a read: http://www.nature.com/news/medical-research-cell-division-1.13273#comments
Image: Some original glass ampoules of WI-38 cells, created in 1962. Copyright Leonard Hayflick.
#ScienceEveryday
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Self-similar polygonal tilings
This picture, by Michael Barnsley and Andrew Vince, shows a self-similar polygonal tiling. These tilings of the plane are reminiscent of the more well known Penrose tilings, although their properties are somewhat different. Barnsley and Vince have many more examples of these tilings in their paper Self-Similar Polygonal Tiling (https://arxiv.org/abs/1611.02218) from November 2016.
The tiling in the picture is a tiling of order 2, which means that there are two different sizes of tiles. All the tiles of a given size are congruent, which means that they are the same shape, or more precisely, that any of them can be transformed into any of the others by a combination of reflections, rotations, and translations. Another important feature of this particular tiling is that all the tiles are similar. This means that the large tiles are simply scaled versions of the small tiles; more precisely, by enlarging by an appropriate scale factor, any of the tiles can be transformed into a tile that is congruent to any of the others.
A tiling is said to be self-similar if it is possible to transform the tiling using a combination of enlargements, reflections, rotations and translations in such a way that the enlarged tiling fits neatly over the original tiling, in the sense that each enlarged tile is a union of some of the original tiles. It is not generally possible to see if a tiling has this property just from looking at a partial picture, like the one shown here.
A tiling is said to be quasiperiodic if, given any patch of tiles, there exists a (possibly large) number R with the property that any disc of radius R in the tiling contains a copy of the patch, up to congruence (i.e., up to reflections, rotations, and translations).
Finally, a self-similar polygonal tiling is a tiling of the plane by similar polygons that is (a) self-similar, (2) quasiperiodic, and (3) of finite order. The authors are interested in the situation in which the tiles can be pieced together to make a larger copy of the same tile, and in which there exists a constant s with the property that the size ratio between any two tiles is an integer power of s. The main result of the paper (Theorem 4.1) shows that, in this situation, there are infinitely many different ways to construct a self-similar polygonal tiling with those particular tiles.
The authors are also interested in tilings using a polygon known as the golden bee. This polygon is shaped roughly like a lower case letter b, and it has the distinction of being the only polygon (other than a non-isosceles right triangle) that can be partitioned into a pair of non-congruent scaled copies of itself. The word golden refers to the fact that the golden ratio plays an important role in the dimensions of the polygon. Perhaps not surprisingly, the tilings arising from the golden bee polygon have close connections to the Fibonacci sequence.
I've posted about tilings several times before; one such post, which links
to another, is here: https://plus.google.com/101584889282878921052/posts/dhPpRnwNmsR
People have been complaining that I haven't posted for a very long time, for which I apologise!
#mathematics #scienceeveryday
This picture, by Michael Barnsley and Andrew Vince, shows a self-similar polygonal tiling. These tilings of the plane are reminiscent of the more well known Penrose tilings, although their properties are somewhat different. Barnsley and Vince have many more examples of these tilings in their paper Self-Similar Polygonal Tiling (https://arxiv.org/abs/1611.02218) from November 2016.
The tiling in the picture is a tiling of order 2, which means that there are two different sizes of tiles. All the tiles of a given size are congruent, which means that they are the same shape, or more precisely, that any of them can be transformed into any of the others by a combination of reflections, rotations, and translations. Another important feature of this particular tiling is that all the tiles are similar. This means that the large tiles are simply scaled versions of the small tiles; more precisely, by enlarging by an appropriate scale factor, any of the tiles can be transformed into a tile that is congruent to any of the others.
A tiling is said to be self-similar if it is possible to transform the tiling using a combination of enlargements, reflections, rotations and translations in such a way that the enlarged tiling fits neatly over the original tiling, in the sense that each enlarged tile is a union of some of the original tiles. It is not generally possible to see if a tiling has this property just from looking at a partial picture, like the one shown here.
A tiling is said to be quasiperiodic if, given any patch of tiles, there exists a (possibly large) number R with the property that any disc of radius R in the tiling contains a copy of the patch, up to congruence (i.e., up to reflections, rotations, and translations).
Finally, a self-similar polygonal tiling is a tiling of the plane by similar polygons that is (a) self-similar, (2) quasiperiodic, and (3) of finite order. The authors are interested in the situation in which the tiles can be pieced together to make a larger copy of the same tile, and in which there exists a constant s with the property that the size ratio between any two tiles is an integer power of s. The main result of the paper (Theorem 4.1) shows that, in this situation, there are infinitely many different ways to construct a self-similar polygonal tiling with those particular tiles.
The authors are also interested in tilings using a polygon known as the golden bee. This polygon is shaped roughly like a lower case letter b, and it has the distinction of being the only polygon (other than a non-isosceles right triangle) that can be partitioned into a pair of non-congruent scaled copies of itself. The word golden refers to the fact that the golden ratio plays an important role in the dimensions of the polygon. Perhaps not surprisingly, the tilings arising from the golden bee polygon have close connections to the Fibonacci sequence.
I've posted about tilings several times before; one such post, which links
to another, is here: https://plus.google.com/101584889282878921052/posts/dhPpRnwNmsR
People have been complaining that I haven't posted for a very long time, for which I apologise!
#mathematics #scienceeveryday
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From Astronomy to Solar Power : An astronomer famous for designing some of the largest telescope mirrors on the planet now has another trick up his sleeve: he wants to build highly efficient solar collectors that produce electricity on the cheap. An Arizona company he founded, REhnu, claims the new design could drive the price of a solar power farm down to $1 per watt by 2020.
Two decades ago, Roger Angel cast a honeycomb-structure mirror 6.5 metres in diameter at the University of Arizona, using a unique spin-casting technique that rotated a furnace several times a minute, so the molten glass inside formed a parabola close to the mirror's final shape. Five years later, he scaled up to 8.4 metres, and the age of giant Earth-based telescopes was in full swing. Today, four 8.2-metre mirrors designed in this way are used in the Very Large Telescope in Chile.
Others have tried solar collectors, but have had a hard time keeping costs down. REhnu gets around this by making its mirrors out of thin sheets of cheap float glass, the stuff used in windows.
Article Link: http://www.newscientist.com/blogs/onepercent/2012/03/an-astronomer-famous-for-desig.html
Rehnu website: http://www.rehnu.com/
#science #scienceeveryday #solar #rehnu #astronomer #solarenergy
Two decades ago, Roger Angel cast a honeycomb-structure mirror 6.5 metres in diameter at the University of Arizona, using a unique spin-casting technique that rotated a furnace several times a minute, so the molten glass inside formed a parabola close to the mirror's final shape. Five years later, he scaled up to 8.4 metres, and the age of giant Earth-based telescopes was in full swing. Today, four 8.2-metre mirrors designed in this way are used in the Very Large Telescope in Chile.
Others have tried solar collectors, but have had a hard time keeping costs down. REhnu gets around this by making its mirrors out of thin sheets of cheap float glass, the stuff used in windows.
Article Link: http://www.newscientist.com/blogs/onepercent/2012/03/an-astronomer-famous-for-desig.html
Rehnu website: http://www.rehnu.com/
#science #scienceeveryday #solar #rehnu #astronomer #solarenergy
2013-06-04
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Starburst Jewel
Like a July 4 fireworks display, a young, glittering collection of stars looks like an aerial burst. The cluster is surrounded by clouds of interstellar gas and dust—the raw material for new star formation. The nebula, located 20,000 light-years away in the constellation Carina, contains a central cluster of huge, hot stars, called NGC 3603. This environment is not as peaceful as it looks. Ultraviolet radiation and violent stellar winds have blown out an enormous cavity in the gas and dust enveloping the cluster, providing an unobstructed view of the cluster.
Most of the stars in the cluster were born around the same time but differ in size, mass, temperature, and color. The course of a star's life is determined by its mass, so a cluster of a given age will contain stars in various stages of their lives, giving an opportunity for detailed analyses of stellar life cycles. NGC 3603 also contains some of the most massive stars known. These huge stars live fast and die young, burning through their hydrogen fuel quickly and ultimately ending their lives in supernova explosions.
Star clusters like NGC 3603 provide important clues to understanding the origin of massive star formation in the early, distant universe. Astronomers also use massive clusters to study distant starbursts that occur when galaxies collide, igniting a flurry of star formation. The proximity of NGC 3603 makes it an excellent lab for studying such distant and momentous events. This Hubble Space Telescope image was captured in August 2009 and December 2009 with the Wide Field Camera 3 in both visible and infrared light, which trace the glow of sulfur, hydrogen, and iron.
Article Link: http://www.wired.com/wiredscience/2013/01/space-photo-of-the-day-2/?pid=6842
Image: NASA, ESA, R. O'Connell (University of Virginia), F. Paresce (National Institute for Astrophysics, Bologna, Italy), E. Young (Universities Space Research Association/Ames Research Center), the WFC3 Science Oversight Committee, and the Hubble Heritage Team (STScI/AURA) [high-resolution]
#science #scienceeveryday #starburst #jewel #spaceoddity #space #galaxy
Like a July 4 fireworks display, a young, glittering collection of stars looks like an aerial burst. The cluster is surrounded by clouds of interstellar gas and dust—the raw material for new star formation. The nebula, located 20,000 light-years away in the constellation Carina, contains a central cluster of huge, hot stars, called NGC 3603. This environment is not as peaceful as it looks. Ultraviolet radiation and violent stellar winds have blown out an enormous cavity in the gas and dust enveloping the cluster, providing an unobstructed view of the cluster.
Most of the stars in the cluster were born around the same time but differ in size, mass, temperature, and color. The course of a star's life is determined by its mass, so a cluster of a given age will contain stars in various stages of their lives, giving an opportunity for detailed analyses of stellar life cycles. NGC 3603 also contains some of the most massive stars known. These huge stars live fast and die young, burning through their hydrogen fuel quickly and ultimately ending their lives in supernova explosions.
Star clusters like NGC 3603 provide important clues to understanding the origin of massive star formation in the early, distant universe. Astronomers also use massive clusters to study distant starbursts that occur when galaxies collide, igniting a flurry of star formation. The proximity of NGC 3603 makes it an excellent lab for studying such distant and momentous events. This Hubble Space Telescope image was captured in August 2009 and December 2009 with the Wide Field Camera 3 in both visible and infrared light, which trace the glow of sulfur, hydrogen, and iron.
Article Link: http://www.wired.com/wiredscience/2013/01/space-photo-of-the-day-2/?pid=6842
Image: NASA, ESA, R. O'Connell (University of Virginia), F. Paresce (National Institute for Astrophysics, Bologna, Italy), E. Young (Universities Space Research Association/Ames Research Center), the WFC3 Science Oversight Committee, and the Hubble Heritage Team (STScI/AURA) [high-resolution]
#science #scienceeveryday #starburst #jewel #spaceoddity #space #galaxy
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I’ve always been mesmerised by watching such things. No matter where I am I like to stop and watch this happening, theres something about their fine tuned speed and accuracy 😉 and on the odd occasion I have maybe anticipated a little in air collision 😜
Murmurations : is the term used to describe birds flocking and swarming in the sky. Very often, it will take just one bird to change the direction of the swarm. While I have written about swarms before, physicist Andrea Cavagna who studies Bose-Einstein condensates has compared the swarming physics to that of a superfluid; atoms which fall into place in a Bose-Einstein condensate. Sounds far-fetched? read on to know more...
Movement : Cavagna was hardly the first scientist to be intrigued by these acrobatics—known, in a rare instance of technical language coinciding with poetry, as “murmurations.” Other animals that travel in groups showing the same uncanny ability to move in apparent unison away from a predator or toward a food source. One 20th-century ornithologist seriously proposed that they coordinated their movements by telepathy. That possibility hasn’t found much support in biology. The other explanation is that a signal to change direction originates with one or a few individuals, probably on the periphery (the ones most likely to see a threat), and travels as a wave front across the flock, like a ripple spreading across a pond from a dropped pebble. It is just an artifact of human vision that we can’t see it happen in real time. But high-speed cameras can capture it, and computers can model the behavior.
Swarm faster than individuals : Princeton biologist Iain Couzin and MIT oceanographer Nicholas Makris have shown that in the presence of a predator, or a potential food source, or an opportunity to spawn, a wave of movement crosses a school of fish five to ten times faster than any one of them can swim—“incredibly well orchestrated,” says Couzin, “like a ballet.” The fish they’ve studied exhibit a threshold response, changing course only when a sufficiently large fraction of their visible neighbors have.
Wave Phenomena : As for starlings, Cavagna and his collaborators have shown recently that each keeps track of the six or seven closest starlings, adjusting its flight to stay in synchrony. In a new paper, they show how a signal originating with a single individual can cross a hundred-yard-wide flock in a fraction of a second, with virtually no distortion or diminution. The equations that describe this are those that govern waves—rather than, say, the diffusion of a gas or liquid. In the broadest sense, the same laws that photons obey are in play when a flock of starlings encounters a peregrine falcon.
Article Link: http://www.smithsonianmag.com/science-nature/how-just-one-bird-can-urge-entire-flock-change-directions-180952426/?no-ist
Related paper: http://www.sciencedirect.com/science/article/pii/S0003347213000432
Swarming behavior: http://people.esam.northwestern.edu/~cristian/research_body.html
Must watch video link: amazing starlings murmuration (full HD) -www.keepturningleft.co.uk
Main pic source : http://www.rspb.org.uk/discoverandenjoynature/discoverandlearn/birdguide/name/s/starling/roosting.aspx
Gif and video source: http://americablog.com/2014/01/stunning-flock-starlings-video.html
Time lapse of bird flight patterns : http://www.visualnews.com/2014/01/27/bird-flights-mapped-into-time-lapse-sky-performances/
#scienceeveryday #sciencesunday #swarm
Movement : Cavagna was hardly the first scientist to be intrigued by these acrobatics—known, in a rare instance of technical language coinciding with poetry, as “murmurations.” Other animals that travel in groups showing the same uncanny ability to move in apparent unison away from a predator or toward a food source. One 20th-century ornithologist seriously proposed that they coordinated their movements by telepathy. That possibility hasn’t found much support in biology. The other explanation is that a signal to change direction originates with one or a few individuals, probably on the periphery (the ones most likely to see a threat), and travels as a wave front across the flock, like a ripple spreading across a pond from a dropped pebble. It is just an artifact of human vision that we can’t see it happen in real time. But high-speed cameras can capture it, and computers can model the behavior.
Swarm faster than individuals : Princeton biologist Iain Couzin and MIT oceanographer Nicholas Makris have shown that in the presence of a predator, or a potential food source, or an opportunity to spawn, a wave of movement crosses a school of fish five to ten times faster than any one of them can swim—“incredibly well orchestrated,” says Couzin, “like a ballet.” The fish they’ve studied exhibit a threshold response, changing course only when a sufficiently large fraction of their visible neighbors have.
Wave Phenomena : As for starlings, Cavagna and his collaborators have shown recently that each keeps track of the six or seven closest starlings, adjusting its flight to stay in synchrony. In a new paper, they show how a signal originating with a single individual can cross a hundred-yard-wide flock in a fraction of a second, with virtually no distortion or diminution. The equations that describe this are those that govern waves—rather than, say, the diffusion of a gas or liquid. In the broadest sense, the same laws that photons obey are in play when a flock of starlings encounters a peregrine falcon.
Article Link: http://www.smithsonianmag.com/science-nature/how-just-one-bird-can-urge-entire-flock-change-directions-180952426/?no-ist
Related paper: http://www.sciencedirect.com/science/article/pii/S0003347213000432
Swarming behavior: http://people.esam.northwestern.edu/~cristian/research_body.html
Must watch video link: amazing starlings murmuration (full HD) -www.keepturningleft.co.uk
Main pic source : http://www.rspb.org.uk/discoverandenjoynature/discoverandlearn/birdguide/name/s/starling/roosting.aspx
Gif and video source: http://americablog.com/2014/01/stunning-flock-starlings-video.html
Time lapse of bird flight patterns : http://www.visualnews.com/2014/01/27/bird-flights-mapped-into-time-lapse-sky-performances/
#scienceeveryday #sciencesunday #swarm
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2014-09-06
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Being a non smoker and a prior smoker I truly believe in remedies a nature and past cultures!!!
"Tobacco Killing Cancer": Say it Ain't So
There's a new research finding making the rounds on sensationalised mass media with breathless headlines about how a molecule from the tobacco plant can 'explode' and kill cancer cells. The work is actually very interesting, but as usual the #ScienceMediaHype is not warranted. So what is it all about?
✤ Scientists were looking at a molecule isolated from the flowers of the ornamental tobacco plant Nicotiana alata. This molecule, named NaD1 derives its name from Nicotiana alata defensin 1. NaD1 is part of a group of molecules known as defensins, which are really interesting in their own right.
✤ What are defensins? They are small protein molecules found across many different species of animals and plants. As their name implies, these molecules function as part of the host innate immune system; they have anti-microbial activity against bacteria, viruses and fungi. As a general rule, defensins bind to the cell membrane of the microbe causing changes to cell membrane structure, allowing essential ions and nutrients to leak out, thereby killing the cell. However, the exact mechanism by which defensins bind to the cell membrane has been unclear up until now.
✤ In this study, scientists identified that the defensin NaD1 binds to a small phosolipid (a lipid molecule with a phosphate molecule attached to it) known as PIP2. This binding results in a NaD1:PIP2 complex which they visualised using transmission electron microscopy. NaD1 is able to polymerise and form long string-like structures in the presence of PIP2. This binding is crucial for NaD1's microbe-killing abilities.
✤ Next, the scientists tested the ability of NaD1 to cause changes in the cell membrane. They used a dye that normally does not cross the cell membrane to monitor cell membrane integrity; if the dye shows up inside the cells, the cell membrane is obviously damaged. Sure enough, NaD1 caused an influx of the dye into the cell, and also leakage of ATP molecules from the cell to the outside. Using scanning laser confocal microscopy, the scientists then visualised the effect of NaD1 on HeLa (cervical cancer) cells. The membrane blebbing (protrusions) and intake of the red dye can be seen in the gif below.
✤ Since PIP2 is found in many different cell types, the scientists also evaluated NaD1's cell membrane destroying capabilities in many different cell types. They found that immortal cells (i.e. tumor cells) were more susceptible to killing by NaD1 than normal cells. This is attributed to the different properties that cancer cell membranes have when compared against normal cell membranes, and the precise mechanism for this is yet to be discovered.
✤ Defensins are really interesting molecules with a whole range of functions. In this study, scientists identified the precise mechanism by which NaD1 destabilises the cell membrane by specifically binding to PIP2. They are capable of forming oligomers to carry out diverse functions within the immune system, and this study explains in detail one such mechanism. This is fascinating in its own right, and does not need to be labelled with a ridiculous 'tobacco plant can cure cancer' label to make it newsworthy!
Full #OpenAccess paper: http://goo.gl/KoZ1XG
Image description: Confocal laser scanning microscope image of NaD1 cells imaged over 10 mins. Video included with paper but handily giff-ed for G+ consumption by +Adam Gill
#ScienceEveryday
There's a new research finding making the rounds on sensationalised mass media with breathless headlines about how a molecule from the tobacco plant can 'explode' and kill cancer cells. The work is actually very interesting, but as usual the #ScienceMediaHype is not warranted. So what is it all about?
✤ Scientists were looking at a molecule isolated from the flowers of the ornamental tobacco plant Nicotiana alata. This molecule, named NaD1 derives its name from Nicotiana alata defensin 1. NaD1 is part of a group of molecules known as defensins, which are really interesting in their own right.
✤ What are defensins? They are small protein molecules found across many different species of animals and plants. As their name implies, these molecules function as part of the host innate immune system; they have anti-microbial activity against bacteria, viruses and fungi. As a general rule, defensins bind to the cell membrane of the microbe causing changes to cell membrane structure, allowing essential ions and nutrients to leak out, thereby killing the cell. However, the exact mechanism by which defensins bind to the cell membrane has been unclear up until now.
✤ In this study, scientists identified that the defensin NaD1 binds to a small phosolipid (a lipid molecule with a phosphate molecule attached to it) known as PIP2. This binding results in a NaD1:PIP2 complex which they visualised using transmission electron microscopy. NaD1 is able to polymerise and form long string-like structures in the presence of PIP2. This binding is crucial for NaD1's microbe-killing abilities.
✤ Next, the scientists tested the ability of NaD1 to cause changes in the cell membrane. They used a dye that normally does not cross the cell membrane to monitor cell membrane integrity; if the dye shows up inside the cells, the cell membrane is obviously damaged. Sure enough, NaD1 caused an influx of the dye into the cell, and also leakage of ATP molecules from the cell to the outside. Using scanning laser confocal microscopy, the scientists then visualised the effect of NaD1 on HeLa (cervical cancer) cells. The membrane blebbing (protrusions) and intake of the red dye can be seen in the gif below.
✤ Since PIP2 is found in many different cell types, the scientists also evaluated NaD1's cell membrane destroying capabilities in many different cell types. They found that immortal cells (i.e. tumor cells) were more susceptible to killing by NaD1 than normal cells. This is attributed to the different properties that cancer cell membranes have when compared against normal cell membranes, and the precise mechanism for this is yet to be discovered.
✤ Defensins are really interesting molecules with a whole range of functions. In this study, scientists identified the precise mechanism by which NaD1 destabilises the cell membrane by specifically binding to PIP2. They are capable of forming oligomers to carry out diverse functions within the immune system, and this study explains in detail one such mechanism. This is fascinating in its own right, and does not need to be labelled with a ridiculous 'tobacco plant can cure cancer' label to make it newsworthy!
Full #OpenAccess paper: http://goo.gl/KoZ1XG
Image description: Confocal laser scanning microscope image of NaD1 cells imaged over 10 mins. Video included with paper but handily giff-ed for G+ consumption by +Adam Gill
#ScienceEveryday
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These Solar-Powered Giant Winged Drones Could Replace Satellites : Titan Aerospace, a small Series A startup from New Mexico, is developing the SOLARA 50, a long-winged plane that will stay aloft for five years at a time, reaching an altitude of 65,000 feet. Titan Aerospace VP Stephen "Ron" Olsen calls the SOLARA 50 an atmospheric satellite and argues that, with a projected cost of less than $10 million, it will be a cheaper, retrievable alternative to conventional satellites.
Though reluctant to talk about specific technologies, Olsen does wax excitedly about the many future applications of the high-flying, solar-powered UAV, including tracking wildlife, mapping fire, patrolling the border, and even providing cellphone coverage to remote areas. "One of these UAVs at 10 miles can replace 100 cell towers," he says. Though some might be discouraged by these failures, the folks at Titan Aerospace believe the relevant technologies—advanced composites, efficient solar cells and lithium batteries—are now mature enough to justify another go at an atmospheric satellite. "We came at the right moment in the timeline," says Cornew. "We are now at the stage that a solar UAV is an assembly job, not an experiment."
Source Article: http://www.popularmechanics.com/technology/aviation/solar-powered-drones-bright-future-15803525
Gizmodo link: http://www.gizmodo.com.au/tags/solara-50/
Company link and pic courtesy: titanaerospace.com
Video Link: Titan Aerospace, Solara 50
Arstechnica link: http://arstechnica.com/information-technology/2013/08/almost-orbital-solar-powered-drone-offered-as-atmospheric-satellite/
#science #scienceeveryday #solar #solarenergy #drones #satellites #mapping
Though reluctant to talk about specific technologies, Olsen does wax excitedly about the many future applications of the high-flying, solar-powered UAV, including tracking wildlife, mapping fire, patrolling the border, and even providing cellphone coverage to remote areas. "One of these UAVs at 10 miles can replace 100 cell towers," he says. Though some might be discouraged by these failures, the folks at Titan Aerospace believe the relevant technologies—advanced composites, efficient solar cells and lithium batteries—are now mature enough to justify another go at an atmospheric satellite. "We came at the right moment in the timeline," says Cornew. "We are now at the stage that a solar UAV is an assembly job, not an experiment."
Source Article: http://www.popularmechanics.com/technology/aviation/solar-powered-drones-bright-future-15803525
Gizmodo link: http://www.gizmodo.com.au/tags/solara-50/
Company link and pic courtesy: titanaerospace.com
Video Link: Titan Aerospace, Solara 50
Arstechnica link: http://arstechnica.com/information-technology/2013/08/almost-orbital-solar-powered-drone-offered-as-atmospheric-satellite/
#science #scienceeveryday #solar #solarenergy #drones #satellites #mapping
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