SciSeek Science Blog

Our Amorphophallus is Smaller

admin — Tue, 07 Feb 2012 21:00:50 +0000

The famed “corpse flower” plant – known for its giant size, rotten-meat odor and phallic shape – has a new, smaller relative: A University of Utah botanist discovered a new species of Amorphophallus that is one-fourth as tall but just as stinky.

The new species, collected on two small islands off Madagascar, brings to about 170 the number of species in the genus Amorphophallus, which is Greek for “misshapen penis” because of the shape of the plants’ flower-covered shaft, called the inflorescence or the spadix, says Greg Wahlert, a postdoctoral researcher in biology.

The 4.5-foot-tall plant, Amorphophallus perrieri, began reeking Friday, Feb. 3 as it approached the peak of its bloom in a campus greenhouse. A day later, Wahlert began cutting down the plant in stages so the spadix, the surrounding leafy spathe and other parts could be pressed, mounted and submitted to the National Museum of Natural History in Paris as part of the process of designating the plant a new species.

That won’t be official until about a year from now after Wahlert publishes a scientific paper formally describing the species, which can grow to 5 feet high, and how it differs from relatives in the genus, including Amorphophallus titanum – also known as the “corpse plant,” “corpse flower” and “titan arum” – which grows to 20 feet high.

After Wahlert first collected specimens of the new plant in 2006 and 2007 and discovered it was a new species, he found the Paris museum’s herbarium held a dried specimen collected from one of the same islands by French botanist-geologist Joseph Marie Henri Perrier de la Bâthie (1873-1958), who didn’t realize it was a new species. So Wahlert is naming it for Perrier.

“Perrier collected it in 1932, and it sat in the museum until we dug it up and compared it to the other specimens and the plants that I had collected,” Wahlert says. “Perrier spent years working on scores of other plant groups [and describing hundreds of other new species] and just never got around to it.”

The corpse flower smells like rotting meat to attract the flies and beetles that pollinate it. Wahlert had expected the new species would smell like cheese, which it did briefly when it began blooming Feb. 3. But the odor soon grew worse – much worse – and more like its giant relative.

“I smelled rotting roadkill out in the sun reeking,” says University of Utah biology Professor Lynn Bohs, in whose lab Wahlert works. “There’s also a note of public restroom – a Porta Potty smell.”

Wahlert added: “I would say carrion and feces. When you get right up to it, it’s really foul and disgusting.”

Another Utah researcher collected volatile gases emitted by the plant “and will identify the components of the smell,” Wahlert says. Only a small group of Amorphophallus species have been tested for odors, but the known aromas range from rotting meat to anise, cheese, dung, fish, urine, spice and chocolate, he adds.

Two weeks before the plant began to bloom, “it was just a little bud sticking out of the dirt,” he says. When it bloomed, the stalk was almost 4 feet tall and the inflorescence or spadix was about 10 inches long. It was yellow, with pollen on the top part. The lower part, hidden by the reddish, leafy spathe, was covered by hundreds of tiny flowers, each a fraction of an inch wide. (Sometimes the entire spadix is referred to informally as the flower.)

“They are just so rude – their appearance and smell,” Bohs says. “Everybody I’ve talked to says they almost started puking when they smelled it. It’s horrid.”

In the Same Family as Philodendrons and Skunk Cabbage

Some thought the plants’ suggestive genus name was horrid. In 2008, Sir David Attenborough said he invented the name “titan arum” for the corpse flower for his BBC series “The Private Life of Plants” because he thought it would be inappropriate to repeatedly refer to Amorphophallus.

Bohs says the genus belongs to the family Araceae, commonly known as the arum or aroid family. The family includes philodendrons, taro root (from which Hawaiians make poi), skunk cabbage and anthurium, a plant common in floral arrangements, with a yellow spadix surrounded by a leafy, red, heart-shaped spathe.

Wahlert says plants in the genus Amorphophallus are found in southern Asia, the South Pacific, Australia and Africa, including Madagascar. Of the 170 or so species in the genus, which first was discovered in 1834, “a lot have been known for 150 years, but one, two or three new species are described every year,” he adds.

A. titanum grows naturally only in Sumatra in Indonesia, although it is found around the world in greenhouses that compete for the largest corpse flower plant. The Guinness Book of Records title currently is held by a New Hampshire specimen that had a spadix measuring 10-feet-2.25-inches tall in 2010. Counting the stem and spadix, A. titanum can reach 20 feet tall, compared with a 5-foot maximum for A. perrieri, which has a longer stem and shorter spadix – about 10 inches long in the case of the one that bloomed on campus.

New Species Collected from a Burial Island

Wahlert collected the new species from Nosy Mitsio and Nosy Ankarea – two islands northwest of Madagascar, which is off the east coast of Africa. “Nosy” means island in the Malagasy language. The plant since has been found on Madagascar.

He had to obtain permission from a local village to visit Nosy Ankarea, an uninhabited, half-mile-wide island where the Sakalava people buried their rulers. Unlike Ankarea, which is still vegetated, Mitsio is heavily deforested. A. perrieri was found there in low scrub behind beach dunes.

“I went there in 2006 to collect tree violets, and when I got there I discovered these Amorphophallus in full bloom on the first day in the field,” cutting and collecting four or five specimens, Wahlert says. “That night I got malaria. I stayed there a week but was so sick I couldn’t do much collecting.”

After the trip, Wahlert showed the specimens to Dutch botanist Wilbert Hetterscheid of Wageningen University. Hetterscheid, an expert on Amorphophallus, said they were a new species, and is co-authoring the descriptive paper with Wahlert.

In October 2007, Wahlert went back to the islands at the end of the dry season, and once again the new species were in full bloom. He collected 15 tubers – the roots – so he could grow the plants.

Wahlert kept the live plants at various institutions where he worked and gave others away, ending up with one left when he moved to Utah last fall.

Why should anyone care about a stinking plant with a suggestive shape?

“It’s not high-tech, but it’s still important to describe new species, to document biodiversity, particularly in a place like Madagascar, which is one of the world’s great biodiversity hotspots,” Wahlert says. “It’s been severely deforested and is continuing to be deforested. So it’s important to document new species before they go extinct.”

Source: University of Utah
Photo 1: Close-up of the reddish-purplish, leafy “spathe” surrounding the central “spadix” of the newly discovered plant species Amorphophallus perrieri, which grows to 5 feet tall. ~ Cameron McIntire, University of Utah.
Photo 2: University of Utah botanist Greg Wahlert stands next to a new plant species he discovered — Amorphophallus perrieri. ~ Lee J. Siegel, University of Utah

Ocean Scientists Shed New Light on Mariana Trench

admin — Tue, 07 Feb 2012 16:00:02 +0000

An ocean mapping expedition has shed new light on deepest place on Earth, the 2,500-kilometer long Mariana Trench in the western Pacific Ocean near Guam. Using a multibeam echo sounder, state-of-the-art equipment for mapping the ocean floor, scientists from the University of New Hampshire Center for Coastal and Ocean Mapping/Joint Hydrographic Center found four “bridges” spanning the trench and measured its deepest point with greater precision than ever before.

Research professor James Gardner and affiliate professor Andrew Armstrong, both of UNH’s Center for Coastal and Ocean Mapping/UNH-NOAA Joint Hydrographic Center (CCOM/JHC), presented their findings at the recent American Geophysical Union meeting in San Francisco, the world’s largest annual meeting of Earth and planetary scientists.

Mapping the entire Mariana Trench – approximately 400,000 square kilometers — from August through October 2010, the researchers discovered four bridges spanning the trench and rising as high as 2,500 meters above its floor. While satellite images had suggested the trench might be spanned by one such ridge, Gardner says the mapping mission confirmed the existence of four such features. “That got me excited,” he says.

The ridges are being formed as the 180-million-year-old Pacific and far younger Philippine tectonic plates collide. Because the ocean’s crust cools as it ages, “the Pacific crust is much, much older, so it’s diving underneath the Philippine plate,” Gardner says. As seamounts on the Pacific plate are pulled beneath the Philippine plate, they are compacted against the wall of the trench, forming these ridges.

“It’s incredibly complex geology. These seamounts haven’t been completely subducted, they’re getting jammed up against the plate,” Gardner says. He surmises that the bridges are related to earthquake subduction zones, such as the one that caused the March 2011 earthquake in Japan.

The expedition also yielded the most precise measurement yet of Challenger Deep, the trench’s (and the Earth’s) deepest point, finding it to be 10,994 meters deep, plus or minus 40 meters. Calculated from thousands of depth soundings as well as detailed analysis of how the how the water column can alter the echo sounding signals, the new measurement is similar to other claims of the Challenger Deep’s depth, some of which are deeper.

“When you’re dealing with something that’s 11 kilometers deep, you have to deal with inherent uncertainties in the system,” says Gardner, noting that Challenger Deep is deeper than Mount Everest is high.

Multibeam echo sounders measure depth by sending sound energy to the ocean floor then analyzing the returning signal. Mounted beneath a ship, the instruments produce a fan-shaped swath of coverage of the seafloor. The resolution of the resulting images, at one pixel to every 100 meters, is far more precise than other earlier measurement systems. Hydrographers and ocean mappers such as Armstrong and Gardner describe the process of mapping an area as like “mowing the lawn,” making overlapping tracks over the area in question.

This mission to the Mariana Trench, the third and fourth cruises to that area by UNH scientists, was undertaken to gather data that can be used to support an extended continental shelf under Article 76 of the United Nations Convention of the Law of the Sea (UNCLOS). All data are publicly available on the CCOM website: www.ccom.unh.edu.

The University of New Hampshire, founded in 1866, is a world-class public research university with the feel of a New England liberal arts college. A land, sea, and space-grant university, UNH is the state’s flagship public institution, enrolling 12,200 undergraduate and 2,300 graduate students.

Source: University of New Hampshire
Photo: Map view of bathymetry of southern Mariana Trench Challenger Deep area. Arrow points to circle that identifies the location of the deepest sounding in the trench (10,994 meters). White contours are 10,000-meter isobath. ~ University of New Hampshire Center for Coastal and Ocean Mapping/Joint Hydrographic Center

Nanorod-Assembled Order Affects Diffusion Rate and Direction

admin — Tue, 07 Feb 2012 13:00:23 +0000

Some of the recent advancements in nanotechnology depend critically on how nanoparticles move and diffuse on a surface or in a fluid under non-ideal to extreme conditions. Georgia Tech has a team of researchers dedicated to advancing this frontier.

Rigoberto Hernandez, a professor in the School of Chemistry and Biochemistry, investigates these relationships by studying three-dimensional particle dynamics simulations on high-performance computers. His new findings, which focus on the movements of a spherical probe amongst static needles, have landed on the cover of February’s The Journal of Physical Chemistry B.

Hernandez and his former Ph.D. student, Ashley Tucker, assembled the rodlike scatterers in one of two states during his simulations: disordered (isotropic) and ordered (nematic). When the nanorods were disordered, pointing in various directions, Hernandez found that a particle typically diffused uniformly in all directions. When every rod pointed in the same direction, the particle, on average, diffused more in the same direction as the rods than against the grain of the rods. In this nematic state, the probe’s movement mimicked the elongated shape of the scatterers. The surprise was that the particles sometimes diffused faster in the nematic environment than in the disordered environment. That is, the channels left open between the ordered nanorods don’t just steer nanoparticles along a direction, they also enable them to speed right through.

As the density of the scatterers is increased, the channels become more and more crowded. The particle diffusing through these increasingly crowded assemblies slows down dramatically in the simulation. Nevertheless, the researchers found that the nematic scatterers continued to accommodate faster diffusion than disordered scatterers.

“These simulations bring us a step closer to creating a nanorod device that allows scientists to control the flow of nanoparticles,” said Hernandez. “Blue-sky applications of such devices include the creation of new light patterns, information flow and other microscopic triggers.”

For example, if scientists need a probe to diffuse in a specific direction at a particular speed, they could trigger the nanorods to move into a specified direction. When they need to change the particle’s direction, scatterers could then be triggered to rearrange into a different direction. Indeed, the trigger could be the absence of sufficient nanoparticles in a given part of the device. The ensuing reordering of the nanorods would then drive a repopulation of nanoparticles that would then be available to perform a desired action, such as to stimulate light flow.

“While this NSF-funded work to better understand the motion of particles within complex arrays at the nanoscale is very fundamental,” Hernandez says, “it has significant long-term implications on device fabrication and performance at such scales. It’s fun to think about and provides great training for my students.”

This project is supported by the National Science Foundation (NSF) (Award Numbers CHE-0749580 and CHE-0946869). The content is solely the responsibility of the principal investigators and does not necessarily represent the official views of the NSF.

Source: Georgia Institute of Technology
Photo: Diffusional behavior of a spherical probe through static nematogens (or needles) is probed via molecular dynamics simulations. ~ The Georgia Institute of Technology

Same Ocean, Different Songs for Southern Indian Ocean Humpbacks

admin — Mon, 06 Feb 2012 20:00:46 +0000

A recently published study by the Wildlife Conservation Society and others reveals that humpback whales on both sides of the southern Indian Ocean are singing different tunes, unusual since humpbacks in the same ocean basin usually all sing very similar songs.

The results of the study—conducted by researchers from WCS, Columbia University, and Australia —contradict previous humpback whale song comparisons. Generally, when song from populations in the same ocean basins are compared, researchers find that the songs contain similar parts or “themes.” The differences in song between the Indian Ocean humpback populations most likely indicate a limited exchange between the two regions and may shed new light on how whale culture spreads.

The paper appears in the January edition of Marine Mammal Science and is available on the journal’s website. The authors of the study include: Anita Murray, formerly of the Wildlife Conservation Society and Columbia University ; Salvatore Cerchio, Yvette Razafindrakoto, and Howard Rosenbaum of the Wildlife Conservation Society; Robert McCauley of Curtin University, Perth, Australia; Curt S. Jenner of the Centre for Whale Research, Fremantle, Australia; Douglas Coughran of the Department of Environment and Conservation, Perth, Australia; and Shannon McKay of the School of Life and Environmental Science, Warrnambool, Australia.

“In the Northern Hemisphere, within an ocean basin whales sing songs that are composed of the same themes. However, whales in the southern Indian Ocean are singing almost completely different songs. Songs from Madagascar and Western Australia only shared one similar theme, the rest of the themes were completely different,” said lead author Anita Murray, who conducted the research while a graduate student at Columbia University and the Wildlife Conservation Society and is currently pursuing her doctorate at the University of Queensland in Australia. “The reason for this anomaly remains a mystery. It could be the influence of singing whales from other ocean basins, such as the South Pacific or Atlantic, indicating an exchange of individuals between oceans which is unique to the Southern Hemisphere.”

The songs of humpback whales are generally sung by male individuals on a population’s winter breeding grounds, migratory routes, and summer feeding grounds. The songs themselves are complex arrangements of parts or “themes,” consisting of ascending and descending wails, moans, and shrieks that are repeated in cycles lasting up to 30 minutes. The transmission of songs between individuals from different populations is likely to occur on feeding grounds or during migration when whales from different populations mix. Or, transmission of song may occur when individual male “troubadours” travel to different breeding grounds between breeding seasons or possibly during the same breeding season.

The research team made recordings of humpback whale songs in two locations in coastal Madagascar and three locations along Western Australia during the 2006 breeding season. Research teams in both regions used hydrophones to record the songs of 19 individual whales. Overall, the authors captured more than 20 hours of whole and partial songs for visual and audio analysis. The comparison revealed few similarities between songs; of the eleven themes recorded in both regions, only one theme was shared by both populations. Due to the limited duration of the study (only one breeding season), researchers point out that continued analysis of songs in Madagascar and Australia are needed to examine the reasons for the limited similarity in repertoire.

Dr. Howard Rosenbaum, Director of WCS’s Ocean Giants Program said: “These song comparisons complement our findings based on other methods, such as those from genetic analysis, to understand how whale populations interact with one another.”

WCS conservationist Salvatore Cerchio added: “We have glimpsed here a snapshot of differences in repertoire between humpback whale populations of the Indian Ocean during a single season. Continued monitoring of these songs can provide us with valuable information on how whale songs are exchanged and how those channels of cultural transmission can be protected in the future.”

WCS has been involved in research on humpback whales since the 1960s, when researchers from the New York Zoological Society (now the Wildlife Conservation Society) discovered that the vocalizations of humpback whales are, in fact, songs, defined as a series of themes that are repeated in cycles. For the past decade, WCS’s Ocean Giants Program has conducted an extensive molecular analysis of humpback whale populations in the southern Atlantic and Indian oceans in an attempt to better define discrete populations.

The humpback whale is a baleen whale that grows up to approximately 50 feet in length. The species has distinctively long pectoral fins and a head with knobs on the top and lower jaw. The slow-swimming species was hunted commercially until the International Whaling Commission protected the species globally in 1966. Current estimates for humpback whale numbers are widely debated. While they are recovering, total population sizes may represent only a small percentage of the original global population.

Source: Wildlife Conservation Society
Photo: S. Cerchio/Wildlife Conservation Society.

Chemists Develop More Efficient Protein Labeling

admin — Mon, 06 Feb 2012 16:00:29 +0000

North Carolina State University researchers have created specially engineered mammalian cells to provide a new “chemical handle” which will enable researchers to label proteins of interest more efficiently, without disrupting the normal function of the proteins themselves or the cells in which they are found.

Protein labeling is used by researchers in a variety of fields to help them understand how these important molecules affect the normal functioning of cells. Currently, proteins are labeled for study simply by fusing them to other fluorescent proteins, which allows researchers to use microscopy to track their movements through a cell. This approach has several drawbacks, however, not least being that the fluorescent proteins are often large enough to affect the function of the protein of interest.

Dr. Alex Deiters, associate professor of chemistry, along with colleague Dr. Jason Chin of the Laboratory of Molecular Biology at the Medical Research Council in Cambridge, U.K., have developed a way to attach a fluorophore – a fluorescent molecule about 20 times smaller than the fluorescent proteins currently in use – to a protein that is expressed in a mammalian cell.

Deiters and Chin developed a special 21st amino acid that they added to cells that were specially engineered to incorporate this amino acid into the protein they wanted to study (there are normally only 20 amino acids). This 21st amino acid has a “chemical handle” that only reacts with a specifically designed fluorophore, but not any cellular components. According to Deiters, “The reaction between the modified protein and the fluorophore is extremely fast, high yielding, and generates a stable link between both reaction partners. This novel methodology enables future cell biological studies that were previously not possible.”

The research appears in the Feb. 5 issue of Nature Chemistry.

“We demonstrate the genetic encoding of a norbornene amino acid using the pyrrolysyl transfer RNA synthetase/tRNACUA pair in Escherichia coli and mammalian cells. We developed a series of tetrazine-based probes that exhibit ‘turn-on’ fluorescence on their rapid reaction with norbornenes. We found that our approach gave us a higher yield of labeled proteins and that the binding reaction was 50 times faster than with current methods,” Deiters says. “Additionally, it took less reagent to complete the reaction, so overall we have a faster, more efficient method for protein labeling, and less chance of interfering with the normal function of the proteins and cells being studied.”

The research was funded by the National Institutes of Health and the National Science Foundation. The Department of Chemistry is part of NC State’s College of Physical and Mathematical Sciences.

Source: North Carolina State University

Where Is Memory Stored?

admin — Mon, 06 Feb 2012 13:00:36 +0000

The University of Haifa is hosting an international conference of leading brain researchers from around the world next week, where the participants will be attempting to answer the question of where and how memory is stored; or in less ordinary terms: “Cell and molecular mechanisms of memory formation”. “The more we know about where and how memory is formed, the better we will be able to treat diseases that are related to the brain’s memory mechanisms, such as Alzheimer’s and Parkinson’s,” says Prof. Kobi Rosenblum, Head of the Department of Neurobiology at the University of Haifa, who is organizing the conference with Dr. Raphael Lamprecht (for more information and a detailed program, visit http://neuro.haifa.ac.il ).

About 30 brain researchers from around the world will be joining another 30 researchers from Israel at the conference, which is taking place on 5-7 February, 2012. All of the participating experts have a background in researching various aspects of memory formation, from the most basic molecular mechanisms to advanced brain imaging. The conference is being organized by the University of Haifa’s Department of Neurobiology, the University’s Haifa Forum for Brain and Behavior, and the international Molecular and Cellular Cognition Society. More than 100 of the latest studies in the field will be presented at the conference.

A special feature will be an open discussion, where Israel Prize winner and faculty member of the University of Haifa’s Department of Psychology Prof. Asher Koriat will argue that describing cognition and describing material mechanisms are two different and distant fields. In other words, he claims that molecular and electrophysiology brain researchers cannot really find explanations for cognitive processes. Dozens of brain researchers will contend with this claim at the open discussion.

“The fact that such a large international conference is being held at the University of Haifa is an indicator of the outstanding basic neurobiology research being conducted at the university and of the significance we assign to this field. I am confident that the conference will bring us another step closer to solving the most complex puzzle of all – the human brain,” says Prof. Rosenblum.

Source: University of Haifa
Photo: Prof. Kobi Rosenblum, Head of the Department of Neurobiology at the University of Haifa, who is organizing the conference with Dr. Raphael Lamprecht. Courtesy of the University of Haifa (photo: Gil Nehushtan)

365 New Species Discovered in Peruvian Park

admin — Sun, 05 Feb 2012 13:00:33 +0000

The Wildlife Conservation Society’s (WCS) Peru program announced today the discovery of 365 species previously undocumented in Bahuaja Sonene National Park (BSNP) in southeastern Peru.

Fifteen researchers participated in the inventory focusing on plant life, insects, birds, mammals, and reptiles. The discovery included: thirty undocumented bird species, including the black-and-white hawk eagle, Wilson’s phalarope, and ash colored cuckoo; two undocumented mammals – Niceforo’s big-eared bat and the Tricolored Bat; as well as 233 undocumented species of butterflies and moths. This expedition was especially important because it was the first time that research of this scale has been carried out in Bahuaja Sonene National Park since it was created in 1996.

“The discovery of even more species in this park underscores the importance of ongoing conservation work in this region,” said Dr. Julie Kunen, WCS Director of Latin America and Caribbean Programs. “This park is truly one of the crown jewels of Latin America’s impressive network of protected areas.”

BSNP contains more than 600 bird species including seven different types of macaw, more than 180 mammal species, more than 50 reptiles and amphibian species, 180 fish varieties, and 1,300 types of butterfly.

Since the 1990s, the Wildlife Conservation Society has been working in Tambopata and Bahuaja Sonene Parks in Peru, and Madidi, Pilon Lajas, and Apolobamba Parks in neighboring Bolivia. The tranboundary region, known as the Greater Madidi Landscape, spans more than 15,000 square miles of the tropical Andes and is considered to be the most biodiverse region on earth.

WCS has helped form more than 20 community-based enterprises in the area that promote the sustainable use of natural resources, such as native honey, subsistence hunting and fishing, ornamental fish cultivation, cacao, handicrafts, and timber. More than 3,000 local people benefit from these community initiatives.

The expedition was supported by BSNP, the Tambopata National Reserve, and local Peruvian NGOs: the Association for Integral Research and Development and Fauna Forever.

The Wildlife Conservation Society saves wildlife and wild places worldwide. We do so through science, global conservation, education and the management of the world’s largest system of urban wildlife parks, led by the Flagship Bronx Zoo. Together these activities change attitudes toward nature and help people imagine wildlife and humans living in harmony. WCS is committed to this mission because it is essential to the integrity of life on Earth.

Source: Wildlife Conservation Society
Photo: Giant leaf frogs are among the 50 reptiles and amphibian species found in the park. Photo by: Andre Baertschi

Biosolar Breakthrough Promises Cheap, Easy Green Electricity

admin — Sat, 04 Feb 2012 21:05:44 +0000

Barry D. Bruce, professor of biochemistry, cellular and molecular biology, at the University of Tennessee, Knoxville, is turning the term “power plant” on its head. The biochemist and a team of researchers have developed a system that taps into photosynthetic processes to produce efficient and inexpensive energy.

Bruce collaborated with researchers from the Massachusetts Institute of Technology and Ecole Polytechnique Federale in Switzerland to develop a process that improves the efficiency of generating electric power using molecular structures extracted from plants. The biosolar breakthrough has the potential to make “green” electricity dramatically cheaper and easier.

“This system is a preferred method of sustainable energy because it is clean and it is potentially very efficient,” said Bruce, who was named one of “Ten Revolutionaries that May Change the World” by Forbes magazine in 2007 for his early work, which first demonstated biosolar electricity generation. “As opposed to conventional photovoltaic solar power systems, we are using renewable biological materials rather than toxic chemicals to generate energy. Likewise, our system will require less time, land, water and input of fossil fuels to produce energy than most biofuels.”

Their findings are in the current issue of Nature: Scientific Reports.

To produce the energy, the scientists harnessed the power of a key component of photosynthesis known as photosystem-I (PSI) from blue-green algae. This complex was then bioengineered to specifically interact with a semi-conductor so that, when illuminated, the process of photosynthesis produced electricity. Because of the engineered properties, the system self-assembles and is much easier to re-create than his earlier work. In fact, the approach is simple enough that it can be replicated in most labs—allowing others around the world to work toward further optimization.

“Because the system is so cheap and simple, my hope is that this system will develop with additional improvements to lead to a green, sustainable energy source,” said Bruce, noting that today’s fossil fuels were once, millions of years ago, energy-rich plant matter whose growth also was supported by the sun via the process of photosynthesis.

This green solar cell is a marriage of non-biological and biological materials. It consists of small tubes made of zinc oxide—this is the non-biological material. These tiny tubes are bioengineered to attract PSI particles and quickly become coated with them—that’s the biological part. Done correctly, the two materials intimately intermingle on the metal oxide interface, which when illuminated by sunlight, excites PSI to produce an electron which “jumps” into the zinc oxide semiconductor, producing an electric current.

The mechanism is orders of magnitude more efficient than Bruce’s earlier work for producing bio-electricity thanks to the interfacing of PS-I with the large surface provided by the nanostructured conductive zinc oxide; however it still needs to improve manifold to become useful. Still, the researchers are optimistic and expect rapid progress.

Bruce’s ability to extract the photosynthetic complexes from algae was key to the new biosolar process. His lab at UT isolated and bioengineered usable quantities of the PSI for the research.

Andreas Mershin, the lead author of the paper and a research scientist at MIT, conceptualized and created the nanoscale wires and platform. He credits his design to observing the way needles on pine trees are placed to maximize exposure to sunlight.

Mohammad Khaja Nazeeruddin in the lab of Michael Graetzel, a professor at the Ecole Polytechnique Federale in Lausanne, Switzerland, did the complex testing needed to determine that the new mechanism actually performed as expected. Graetzel is a pioneer in energy and electron transfer reactions and their application in solar energy conversion.

Michael Vaughn, once an undergraduate in Bruce’s lab and now a National Science Foundation (NSF) predoctoral fellow at Arizona State University, also collaborated on the paper.

“This is a real scientific breakthrough that could become a significant part of our renewable energy strategy in the future,” said Lee Riedinger, interim vice chancellor for research. “This success shows that the major energy challenges facing us require clever interdisciplinary solutions, which is what we are trying to achieve in our energy science and engineering PhD program at the Bredesen Center for Interdisciplinary Research and Graduate Education of which Dr. Bruce is one of the leading faculty.”

The Bredesen Center is a joint UT/Oak Ridge National Laboratory academic unit. Bruce is also a co-principal investigator and scientific thrust leader in TN: SCORE, the Tennessee Solar Conversion and Storage Using Outreach, Research and Education. The $20 million project is funded by the NSF and focuses on promoting research and education on solar energy problems across Tennessee. Additionally, he co-founded and is associate director of UT’s Sustainable Energy Education.

Bruce’s work is funded by the Emerging Frontiers Program at the National Science Foundation.

Source: University of Tennessee

Studying Butterfly Flight to Help Build Bug-Size Flying Robots

admin — Sat, 04 Feb 2012 19:05:08 +0000

To improve the next generation of insect-size flying machines, Johns Hopkins engineers have been aiming high-speed video cameras at some of the prettiest bugs on the planet. By figuring out how butterflies flutter among flowers with amazing grace and agility, the researchers hope to help small airborne robots mimic these maneuvers.

U.S. defense agencies, which have funded this research, are supporting the development of bug-size flyers to carry out reconnaissance, search-and-rescue and environmental monitoring missions without risking human lives. These devices are commonly called micro aerial vehicles or MAVs.

“For military missions in particular, these MAVs must be able to fly successfully through complex urban environments, where there can be tight spaces and turbulent gusts of wind,” said Tiras Lin, a Whiting School of Engineering undergraduate who has been conducting the high-speed video research. “These flying robots will need to be able to turn quickly. But one area in which MAVs are lacking is maneuverability.”

To address that shortcoming, Lin has been studying butterflies. “Flying insects are capable of performing a dazzling variety of flight maneuvers,” he said. “In designing MAVs, we can learn a lot from flying insects.”

Lin’s research has been supervised by Rajat Mittal, a professor of mechanical engineering. “This research is important because it attempts to not only address issues related to bio-inspired design of MAVs, but it also explores fundamental questions in biology related to the limits and capabilities of flying insects,” Mittal said.

To conduct this study, Lin has been using high-speed video to look at how changes in mass distribution associated with the wing flapping and body deformation of a flying insect help it engage in rapid aerial twists and turns. Lin, a junior mechanical engineering major from San Rafael, Calif., recently presented some of his findings at the annual meeting of the American Physical Society’s Division of Fluid Dynamics. The student also won second-prize for his presentation of this research at a regional meeting of the American Institute of Aeronautics and Astronautics.

“Ice skaters who want to spin faster bring their arms in close to their bodies and extend their arms out when they want to slow down,” Lin said. “These positions change the spatial distribution of a skater’s mass and modify their moment of inertia; this in turn affects the rotation of the skater’s body. An insect may be able to do the same thing with its body and wings.”

Butterflies move too quickly for someone to see these wing tactics clearly with the naked eye, so Lin, working with graduate student Lingxiao Zheng, used high-speed, high-resolution videogrammetry to mathematically document the trajectory and body conformation of painted lady butterflies. They accomplished this with three video cameras capable of recording 3,000 one-megapixel images per second. (By comparison, a standard video camera shoots 24, 30 or 60 frames per second.)

The Johns Hopkins researchers anchored their cameras in fixed positions and focused them on a small region within a dry transparent aquarium tank. For each analysis, several butterflies were released inside the tank. When a butterfly veered into the focal area, Lin switched on the cameras for about two seconds, collecting approximately 6,000 three-dimensional views of the insect’s flight maneuvers. From these frames, the student typically homed in on roughly one-fifth of a second of flight, captured in 600 frames. “Butterflies flap their wings about 25 times per second,” Lin said. “That’s why we had to take so many pictures.”

The arrangement of the three cameras allowed the researchers to capture three-dimensional data and analyze the movement of the insects’ wings and bodies in minute detail. That led to a key discovery.

Earlier published research pointed out that an insect’s delicate wings possess very little mass compared to the bug’s body. As a result, those scholars concluded that changes in spatial distribution of mass associated with wing flapping did not need to be considered in analyzing an insect’s flight maneuverability and stability. “We found out that this commonly accepted assumption was not valid, at least for insects such as butterflies,” Lin said. “We learned that changes in moment of inertia, which is a property associated with mass distribution, plays an important role in insect flight, just as arm and leg motion does for ice skaters and divers.”

He said this discovery should be considered by MAV designers and may be useful to biologists who study insect flight dynamics.

Lin’s newest project involves even smaller bugs. With support from a Johns Hopkins Provost’s Undergraduate Research Award, he has begun aiming his video cameras at fruit flies, hoping to solve the mystery of how these insects manage to land upside down on perches.

The insect flight dynamics research was funded by the U.S. Air Force Office of Scientific Research and the National Science Foundation.

Source: Johns Hopkins University
Photo 1: Johns Hopkins undergraduate Tiras Lin used high-speed video cameras to analyze the flight dynamics of painted lady butterflies. Photo by Will Kirk/homewoodphoto.jhu.edu
Photo 2: The butterfly research will aid the development of flying bug-size robots. Pictured is an insect-inspired flapping-wing micro air vehicle under development at Harvard. Photo provided by Robert J. Wood, associate professor, and Pratheev Sreetharan, Harvard Microrobotics Lab, Harvard University.
Photo 3: Tiras Lin, who is conducting the butterfly research, is a Johns Hopkins junior majoring in mechanical engineering. Photo by Will Kirk/homewoodphoto.jhu.edu

Hubble Zooms in on a Magnified Galaxy

admin — Sat, 04 Feb 2012 09:39:33 +0000

Thanks to the presence of a natural “zoom lens” in space, NASA’s Hubble Space Telescope got a uniquely close-up look at the brightest “magnified” galaxy yet discovered.

This observation provides a unique opportunity to study the physical properties of a galaxy vigorously forming stars when the universe was only one-third its present age.

A so-called gravitational lens is produced when space is warped by a massive foreground object, whether it is the Sun, a black hole, or an entire cluster of galaxies. The light from more-distant background objects is distorted, brightened, and magnified as it passes through this gravitationally disturbed region.

A team of astronomers led by Jane Rigby of NASA’s Goddard Space Flight Center in Greenbelt, Md., aimed Hubble at one of the most striking examples of gravitational lensing, a nearly 90-degree arc of light in the galaxy cluster RCS2 032727-132623. Hubble’s view of the distant background galaxy is significantly more detailed than could ever be achieved without the help of the gravitational lens.

The results are published today in The Astrophysical Journal, in a paper led by Keren Sharon of the Kavli Institute for Cosmological Physics at the University of Chicago. Professor Michael Gladders and graduate student Eva Wuyts of the University of Chicago were also key team members.

The presence of the lens helps show how galaxies evolved from 10 billion years ago to today. While nearby galaxies are fully mature and are at the tail end of their star-formation histories, distant galaxies tell us about the universe’s formative years. The light from those early events is just now arriving at Earth. Very distant galaxies are not only faint but also appear small on the sky. Astronomers would like to see how star formation progressed deep within these galaxies. Such details would be beyond the reach of Hubble’s vision were it not for the magnification made possible by gravity in the intervening lens region.

In 2006 a team of astronomers using the Very Large Telescope in Chile measured the arc’s distance and calculated that the galaxy appears over three times brighter than previously discovered lensed galaxies. In 2011 astronomers used Hubble to image and analyze the lensed galaxy with the observatory’s Wide Field Camera 3.

The distorted image of the galaxy is repeated several times in the foreground lensing cluster, as is typical of gravitational lenses. The challenge for astronomers was to reconstruct what the galaxy really looked like, were it not distorted by the cluster’s funhouse-mirror effect.

Hubble’s sharp vision allowed astronomers to remove the distortions and reconstruct the galaxy image as it would normally look. The reconstruction revealed regions of star formation glowing like bright Christmas tree bulbs. These are much brighter than any star-formation region in our Milky Way galaxy.

Through spectroscopy, the spreading out of light into its constituent colors, the team plans to analyze these star-forming regions from the inside out to better understand why they are forming so many stars.

For images and more information about galaxy RCS2 032727-132623 and gravitational lensing, visit:

http://hubblesite.org/news/2012/08

http://www.nasa.gov/hubble

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center in Greenbelt, Md., manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Md., conducts Hubble science operations. STScI is operated by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.

Source: Space Telescope Science Institute (STScI)
Photo: NASA, ESA, J. Rigby (NASA Goddard Space Flight Center), K. Sharon (Kavli Inst. for Cosmological Physics, Univ. of Chicago), and M. Gladders and E. Wuyts (Univ. of Chicago)

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