‘Trojan’ cells take on drug-resistant tumours

Written by Science Knowledge on 8:06 AM

JUST one imitation horse was enough to conquer Troy, but it takes two waves of “Trojan” cell fragments to destroy drugresistant tumours in mice. The first wave releases RNA to disrupt drug resistance, making the tumours vulnerable, and the second delivers a fatal dose of chemotherapy. Himanshu Brahmbhatt and Jennifer MacDiarmid of the company Engeneic in Sydney, Australia, had already coaxed bacteria such as E. coli into dividing at their ends, rather than in the middle. This way they produce tiny buds of cytoplasm devoid of chromosomes and other organelles. After washing these “minicells” clear of bacterial toxins , the team loaded them up with chemotherapy drugs and tagged them with antibodies that bind only to tumours. When injected, the minicells destroyed tumours in animals .

However, because many tumours eventually become resistant to chemotherapy, the next step is to find ways to overcome drug resistance. One way cancer cells develop resistance is by overproducing a protein called MDR1, which helps pump the drugs out of the cell, reducing their toxicity. Brahmblatt’s team wondered if they could also use the minicells to block production of this protein. To find out, they created strands of small interfering RNA (siRNA) with a sequence designed to block the expression of the gene for MDR1, and loaded these into the minicells.

Next they injected these minicells into mice with a range of drug-resistant human cancers, including breast, colon and uterine tumours. The minicells were engulfed by the cancer cells, where they released the strands of siRNA (see diagram). The second wave of minicells containing high doses of the cancer drug doxorubicin was then injected, and the tumours shrank, indicating that the first batch had indeed blocked MDR1 (Nature Biotechnology, DOI: 10.1038/ nbt.1547). All of the treated mice were still alive 110 days after being implanted with the tumours, while a group of untreated mice had died by then. Brahmblatt says that the cancer cells engulf the minicells in their cell membranes – a process called endocytosis. Many different cells take in foreign cells or proteins this way, but it wasn’t clear that cancer cells would be capable of absorbing two rounds of minicells. “The first Trojan horse goes in and the cancer cell opens its door,” says Brahmbhatt. “The cell then regenerates its entire machinery for the next Trojan horse to come in and release a different payload.” Brahmbhatt adds that the minicells could be loaded with different drugs depending on the type of cancer and with different siRNAs to block the production of proteins responsible for other forms of drug resistance.

Double whammy to kill cancer cells

They could also be used to treat other diseases. siRNAs have been touted as a way to block a range of disease-causing genes but researchers have struggled to get them across cell membranes efficiently. “This is an exciting, novel technology with potential applicability to a number of different delivery problems,” agrees Daniel Anderson, who researches drugs delivery at the Massachusetts Institute of Technology. Linda Geddes

Does your brain make sweet music?

Written by Science Knowledge on 8:03 AM

WHAT does the human brain sound like? Now you can find out thanks to a technique for turning its flickering activity into music. Listening to scans may also give new insights into the differences and similarities between normal and dysfunctional brains. Brain scans created using functional MRI consist of a series of images in which different areas light up with varying intensity at different times. These can be used to determine which parts of the brain are active during a particular task. To turn such scans into music, philosopher Dan Lloyd at Trinity College in Hartford, Connecticut, identified regions that become active together and assigned each of these groups a different pitch. He then created software that analyses a series of scans and generates the notes at these pitches as the corresponding brain areas light up. Each note is played at a volume that corresponds to the intensity of activity.

When Lloyd fed the software a set of scans of his own brain taken as he switched between driving a virtual-reality car and resting, he found that he could detect the switch-over in the sounds. Lloyd then gave the software scans taken from volunteers with dementia and schizophrenia, and from healthy volunteers. The brains of people with schizophrenia switched between low and high activity more erratically than healthy brains, allowing the two types of brain to be distinguished by sound alone. While this difference is also clear from looking at the images, Lloyd’s collaborator Vince Calhoun at the University of New Mexico in Albuquerque, says there are variations in the music from people with schizophrenia that are not visually obvious. “It almost sounds like there is more background warbling,” he says. He suggests that these “unsteady rhythms and cadences” may be indicative of dysfunction in the brain. Lloyd also identified sounds and rhythms in the brains of people with dementia that distinguished them from healthy volunteers. Could identifying such aural differences ever be useful? Daniel Levitin , a neuroscientist at McGill University in Montreal, Canada, thinks they might. He says brain music’s killer application might be in allowing researchers to home in on patterns that suggest a particular region is interesting and that wouldn’t be detectable using the eye alone. They could analyse these regions more closely using conventional imaging. His colleague Didier Grandjean at the University of Geneva in Switzerland says that brain music might help identify temporal patterns in particular. “Melodies are a much better way to build complex mental representations over time than anything the eye can do,” he says. Lloyd is also keen to explore the aesthetic aspects of brain music. “It’s not quite like composed sound but it’s not random either, it’s ‘almost music’. My students are putting it on their playlists.”


Turning brain activity into music
How brain activity from scans can be turned into a symphony
1: Areas of the brain that activate at the same time are assigned a particular note on a scale

2: A series of brain scans are fed into software that plots their activity levels against time

3: The notes are combined, with volumes varying with brain activity

Source of Information : New Scientist July 4 2009

A premium plan for the neediest

Written by Science Knowledge on 11:33 PM

Could insurance giants save the world’s poor from the effects of climate change?

AS WESTERN governments dither at the negotiating table over how to help the world’s poorest people cope with climate change, some unlikely saviours have stepped up to the plate: the giants of the global insurance industry. As well as providing protection from the increasingly unpredictable weather, the premiums could also be a powerful way to get poor people to adapt to climate change by encouraging them to invest in measures like drought-resistant crops. Is this profit-driven endeavour too good to be true?

Each year, people in the small Ethiopian village of Adi Ha depend on the precise timing of the rain to grow teff, a sourtasting grain they turn into the traditional injera flatbread. If the rains fail, so do their livelihoods. Climate models forecast that droughts, floods, heatwaves and severe storms are destined to become more frequent, so what can poor farmers do? US and European farmers buy crop insurance to cope with extreme weather. But the cost of checking claims from smallholder farmers in developing countries is prohibitive, and so insurance companies have tended to steer clear of them. Now a different type of insurance scheme is being rolled out in Adi Ha and many other places in Africa, Latin America and Asia, backed by corporate giants such as Swiss Re and
Munich Re . Instead of insuring against lost crops, “index insurance” protects farmers against the vagaries of the weather.

For example, if rain gauges at local weather stations drop below a certain level, insurance companies can automatically transfer a payout to farmers without having to visit them. Cover is tailored to each region. In Adi Ha, where farmers need the rains to start before a certain date, those who are insured will receive a payment if rains fail to come before an agreed cut-off date. In the hurricane-prone Caribbean, hotel owners can buy insurance that pays out if winds exceed a certain speed. The premiums can cost as little as a few dollars a year. The scheme in Ethiopia is backed by Swiss Re, but like others of its kind, it only got off the ground because of the firm’s collaborators, in this case Oxfam and the
International Research Institute for Climate and Society (IRI) at Columbia University, New York. Alliances between NGOs, charities and insurance firms may seem an unlikely match. “Oxfam went through a big soul-searching process before climbing on board microinsurance projects, and ultimately decided it made sense,” says Marjorie Victor of Oxfam America. “Insurance companies have surprisingly aligned interests with NGOs when it comes to reducing risk.” According to Molly Hellmuth of IRI, “the trick is to balance the needs of companies to make a profit with the needs of farmers”. At a session on insurance and climate change held in March in Copenhagen, Pablo Suarez , a researcher who has consulted on insurance projects for Oxfam and the UN Development Programme , confessed that he initially approached the idea with a degree of scepticism, but now calls himself a “convert”. Heavyweight humanitarians are also backing the idea. Kofi Annan, former secretary-general of the UN and head of the Global Humanitarian Forum , has said


Source of Information : New Scientist July 4 2009

Why does Coke from a glass bottle, a plastic bottle and an aluminum can taste different?

Written by Science Knowledge on 11:59 PM

It doesn’t. That’s what Coca-Cola’s spokespeople say, anyway. “The great taste of
Coca-Cola is the same regardless of the package it comes in,” they insist. Rather, they say, “the particular way that people choose to enjoy their Coke can affect their perception of taste.” Sure, most people would agree that the cola is indeeddelicious and refreshing, and pouring it into a glass or serving it over ice could influence the sensation of its flavor. But is it possible that the subtle variation in taste that some notice among aluminum cans, plastic bottles and glass bottles is more than just a psychological effect of their soda-consumption rituals?

Given that the formula is always the same, yes, according to Sara Risch, a food chemist and member of the Institute of Food Technologists. “While packaging and food companies work to prevent any interactions, they can occur,” she says. For example, the polymer that lines aluminum cans might absorb small amounts of soluble flavor from the soda. Conversely, acetaldehyde in plastic bottles might migrate into the soda. The FDA regulates this kind of potential chemical contact, but even minute, allowable amounts could alter flavor. Your best bet for getting Coke’s pure, unaltered taste is to drink it from a glass bottle, the most inert material it’s served in. Even that’s not a sure bet, though. Coca-Cola maintains strict uniformity in processes in all of its worldwide bottling facilities, but it concedes that exposure to light and how long the product sits on store shelves may affect the taste. So yeah, the packaging might mess with Coke’s flavor, but we’ll still take it any day over New Coke.—DOUG CANTOR

Source of Information : Popular Science July 2009

If a mosquito bites me after I’ve had a beer, can it get drunk?

Written by Science Knowledge on 8:30 AM

Shockingly, no major studies have been conducted on this topic. “The implications are, however, profound,” says Michael Raupp, an entomologist at the University of Maryland. “Reckless flying, passing out in frosty beer mugs, hitting on crane flies instead of mosquito babes. Frightening!” Fortunately, enough related research exists to make an educated guess. First, does alcohol affect a mosquito’s simple nervous system the way it does creatures with complex brains, such as dogs or Mickey Rourke? In labs, honeybees fly upside-down after alcohol exposure, and inebriated fruit flies have trouble staying upright and fare poorly on learning tests. This suggests that mosquitoes can get tipsy.
Now, how much alcohol does it take to get them schnockered? Scientists routinely puff ethanol vapors at insects and measure their sensitivity with devices called inebriometers. Bugs are no lightweights, often withstanding vapor concentrations of 60 percent alcohol, far more than what’s in our blood after a couple beers. “Someone who’s had 10 drinks might have a blood alcohol content of 0.2 percent,” says entomologist Coby Schal of North Carolina State University. To a mosquito, a blood meal that contains 0.2 percent alcohol is like drinking a beer diluted 25-fold. Skeeters might have developed this Ruthian ability to hold their liquor through diet. They also feed on fermenting fruit and plants, which contain at least 1 percent alcohol and might have boosted their tolerance. And in a mosquito, alcohol (and any fluid other than blood) is diverted to a “holding pouch,” where enzymes break it down before it hits the nervous system.
Before you try to drink a mosquito under the table, heed this warning from Michael Reiskind, an entomologist at Oklahoma State University: The blood alcohol levels required to do so would almost certainly kill you as well.—BJORN CAREY

Source of Information : Popular Science July 2009

A SOLAR-POWERED BOILER

Written by Science Knowledge on 8:24 AM

HEATING YOUR HOME’S WATER SUPPLY WITHOUT USING GAS OR OIL

Why use natural gas or oil to heat your home’s water supply when the sun can do it for free? The big boiler in the sky lays down 100 watts of power across a single square foot. The simple solar-powered hotwater system that I’ve built from scratch will put these free watts to work on the rooftop of my new eco-conscious home. Once I get it installed, it will generate about 450 gallons of hot water a day, plenty for my family of four, while consuming half the amount of energy of a conventional hot-water system. Plus, it will fuel my home’s radiant heating system, a series of polyethylene pipes built into the floor that use hot water to warm the house. The first step is to build two 150- square-foot solar collectors—tidy sandwiches of glass, copper tubes, aluminum sheets and foam insulation held together by a pair of aluminum frames. I’ll position the panels at 65 degrees to the plane of the roof, facing south, like my house, to catch as much sun as possible to heat up the fluid (the antifreeze glycol) flowing through the copper tubes. Next I’ll install a pair of insulated 158-gallon storage tanks in the basement to hold my supply of municipal water. To heat it up, a pump will circulate hot glycol from the collectors through a heat exchanger inside each tank. When sensors in the roof-mounted panels hit about 60°F, a controller automatically turns a valve to start circulating the glycol. One tank distributes water for showers and dishes while the other services the radiant floors. What happens during the winter when the sun’s intensity wanes? That’s where heat from my newly drilled geothermal well comes in. More on that project next month.—JOHN B. CARNETT

Source of Information : Popular Science July 2009

Cleaner fossil fuels

Written by Science Knowledge on 8:14 AM

Carbon-restricting legislation, if enacted, will discourage the use of coal, the dirtiest of all fossil fuels. Natural gas is cleaner but still emits carbon dioxide when burned. Both will be used for decades, but carbon-capture technology could clean them up until they can be replaced completely.

where we are now: 1,460 GW
what we NEED by 2050: 3,830 GW (all of it clean)

CAPTURE THE CARBON
The Dynegy power plant in
Moss Landing, California, could
be the first to use Calera’s
carbon-to-cement emissionsscrubbing
technology.


Tech to watch: Carbon-to-cement
Electricity generation accounts for 35 percent of human-generated carbon dioxide emissions globally, and almost all of that comes from burning coal or natural gas. Production of cement— 2.9 billion tons of it worldwide every year—contributes another 5 percent of carbon dioxide every year. For the Silicon Valley start-up Calera, those are convenient facts. The company has found a way to slash emissions from two of the biggest greenhouse-gas sources simultaneously by turning carbon dioxide into the raw material for buildings and highways. The basics are simple. Take the smokestack exhaust from a coal- or gas-fired power plant and run it through seawater. The carbon dioxide and other pollutants in the flue gases combine with magnesium and calcium in the seawater to form a kind of synthetic limestone. That material can then be processed into either cement or aggregate, the main ingredients in concrete and asphalt. The seawater, which is clean but depleted of magnesium and calcium, is sent back to the ocean. The technology is obviously best suited to the coasts, but inland, briny water drawn from overtapped aquifers could replace seawater. Calera’s process has a side benefit that could make it particularly attractive to the owners of existing coal- and gas-fired power plants: It traps the socalled criteria pollutants—sulfur dioxide, nitrogen oxides, particulates, heavy metals—that the Clean Air Act requires power plants to “scrub” from their smokestacks by 2012. Roughly half the plants in the U.S. haven’t complied with the law, because of the expense and the fact that 20 percent of the electricity a plant produces would have to be used for scrubbing. Add a scrubber to separate out carbon—the most conventional route to clean coal—and you eat up another 20 percent. Total cost: $1.7 billion for a 500-megawatt plant. “If you own an old coal plant that’s already at 35 percent efficiency, you’re pretty much out of business,” says Calera CEO Brent Constantz. In contrast, he estimates, it would cost $400 million for a 500-megawatt plant to install his company’s technology.—H.R.

Source of Information : Popular Science July 2009

Safer Nuclear

Written by Science Knowledge on 8:49 AM

It’s nearly impossible to imagine making meaningful carbon dioxide reductions without designing safer, cleaner reactors and rolling them out immediately—because no one wants to build more of the reactors we have today.

where we are now: 372 GW
what we need by 2050: 700 GW

Tech to watch: Next generation nuclear
Of all carbon-free energy sources, nuclear power is the only one that’s already working on a large scale, generating 21 percent of America’s electricity. It’s also the one that freaks people out the most. Memories of Chernobyl, fears of terrorists getting nuclear material, and unease over waste that stays radioactive for tens of thousands of years all mean that before nuclear power can be expanded on an order needed to meet greenhouse-gas-reduction targets, engineers will need to build new reactors that help mitigate the unique dangers of nuclear fission. In the short term, we’ll have to settle for so-called Generation III+ reactors—simpler, safer and cheaper versions of the water-cooled behemoths that dot the landscape today. But 20 to 30 years down the line, things start to get much more interesting. Here’s a look at the next few decades of nuclear power.—SEÁN CAPTAIN



Generation III+
DESIGN Pressurized water

HOW IT WORKS. Like today’s reactors, these bathe enriched uranium fuel in water that absorbs heat to make steam.

PROMISE. Gen III+ pressurized-water reactors add “passive” safety mechanisms that cool the reactor if the plant loses power. For example, in an emergency, water flows from an extra tank above the reactor, driven by gravity.

PROBLEMS. Radioactive waste takes years to cool before it can be stored in underground repositories, which still don’t exist.

STATUS. Mitsubishi-Westinghouse, which developed the design, has received approval from the U.S. Nuclear Regulatory Commission and has signed contracts to build six reactors in the U.S. and four in China.



Generation IV
DESIGN. Pebble bed

HOW IT WORKS. Tennis-ball-size graphite spheres (pebbles) filled with uranium dioxide fuel capsules are stacked in the reactor like gumballs, where they start a nuclear reaction. A pump sends helium into the reactor, where it flows around the pebbles, absorbs heat, and then drives a turbine.

PROMISE. If the coolant is lost, the graphite pebbles absorb enough heat to prevent the fuel from melting down.

PROBLEMS. A single reactor requires billions of perfectly manufactured fuel capsules. If oxygen seeps in, the fuel can catch fire. The reactor uses enriched uranium (also good for making bombs) and produces radioactive waste.

STATUS. Researchers have built and run small test reactors, but the design hasn’t been commercialized.



Generation V
DESIGN. Traveling wave

HOW IT WORKS. Enriched uranium starts the process, releasing neutrons that help convert scrap depleted uranium (left over from enrichment plants) into plutonium. The plutonium releases yet more neutrons that convert more depleted uranium into usable fuel.

PROMISE. Very little enriched uranium is required, and there is already enough to last for centuries using this technology.

PROBLEMS. Cooling the reactor could require molten sodium, which catches fire if it comes into contact with oxygen or water. No one has built even an experimental traveling-wave reactor.

STATUS. A think tank called Intellectual Ventures wants to build a plant by 2020, but outside experts are skeptical, saying it could take decades.

Source of Information : Popular Science July 2009

Wind power

Written by Science Knowledge on 11:25 PM

Wind power is all about location—getting turbines where the breeze blows steady and strong. One of the best places for that is far out at sea. And because one of the biggest obstacles to expanding wind power is overcoming the objections of residents who don’t want wind farms blocking their views, deepwater wind, which is invisible from shore, has dual appeal.

where we are: 94 GW what we need by 2050: 2,000 GW


Tech to watch: Deepwater wind
According to the U.S. Department of the Interior, seabound wind farms off the Pacific coast could generate 900 gigawatts of electricity every year. Unfortunately, the water there is far too deep for even the tallest windmills to touch bottom. An experiment under way off the coast of Norway, however, could help put them anywhere. The project, called Hywind, is the world’s first large-scale deepwater wind turbine. Although it uses a fairly
standard 152-ton, 2.3-megawatt turbine, Hywind represents “totally new technology,” says Walter Musial, the principal engineer for ocean renewable energy at the National Renewable Energy Laboratory of the U.S. Department of Energy. The turbine will be mounted 213 feet above the water on a floating platform, or spar—a technology Hywind’s creator, the Norwegian company StatoilHydro, draws from its experience as Scandinavia’s largest gas and oil company. The steel spar, which is filled with ballast and extends 328 feet below the sea surface, will be tethered to the ocean floor by three cables; these will stabilize the platform and prevent the turbine from bobbing excessively in the waves. Hywind’s stability in the turbulent, wintry Scandinavian sea would prove that even the deepest corners of the ocean are suitable for wind power. If all goes according to plan, the turbine will start generating electricity six miles off the coast of southwestern Norway as early as September. To produce electricity on a large scale, a commercial wind farm will have to use bigger turbines than Hywind does, but it’s difficult enough to balance such a large turbine so high on a floating pole in the middle of the ocean. To make that turbine heavier, the whole rig’s center of gravity must be moved much closer to the ocean’s surface. To do that, StatoilHydro plans to engineer a new kind of wind turbine, one whose gearbox (the mechanism that transfers power between the rotor and the generator) sits at sea level rather than behind the blades. Hywind is a test run, but the payoff for perfecting floating wind-farm technology could be enormous. Out at sea, the wind is often stronger and steadier than close to shore, where all existing offshore windmills are planted. Deep-sea farms are invisible from land, which helps overcome the windmill-as-eyesore objection that has derailed wind farms in the past. If the technology catches on, it will open up vast swaths of the planet’s surface to one of the best low carbon power sources available.—H.R.

Source of Information : Popular Science July 2009

Biofuels

Written by Science Knowledge on 12:08 AM

Ethanol is the most widely used biofuel today, but it’s hardly a panacea to our energy woes. Researchers are scrambling to transform moreefficient organic materials switchgrass, sugarcane, algae, sewage and even medical waste—into low-emission fuel for both transportation and electricity generation.

where we are: 643,000 barrels per day
what we need by 2050: 34 million per day

TECH TO WATCH: algae
The canals of Venice, Italy, may soon provide a green power source for the city’s seaport and prove that algae-derived energy can meet commercial electricity demand. A $272.6-million plant is awaiting authorization to generate electricity by burning biodiesel fuel made from canal algae. To get the fuel for the plant, algae harvested from the canal will be cultivated in 26-foot plastic bioreactors (and fertilized with carbon dioxide from the plant itself), dried, expellerpressed to squeeze oil-like lipids from the dried biomass, and turned into biodiesel through the addition of lye. By 2011, the plant could generate 40 megawatts, which would be used to power the city’s seaport and channel the excess electricity—33 megawatts—to docked tankers and cruise ships, all with zero net carbon emissions. The Venice project won’t be costeffective; it’s designed as a technology demonstrator and to give the city a jump on expected stricter cap-and-trade legislation. In the meantime, however, other innovations promise to finally make algal power affordable. While centrifuges account for 34 percent of the total investment costs, there is now a cheaper way to separate the algae from the water they grow in. In March, AlgaeVenture Systems in Ohio announced a new method to “dewater” algae using capillary action: A superabsorbent polymer pulls water molecules through a membrane and leaves the algae dry. The company claims that the process reduces biofuel production costs from $875 per ton to just $1.92. Advances in algal oil extraction and the conversion to biodiesel should bring expenses down even further. Although there are currently no plans for a commercial plant in the U.S., companies like BioProcess Algae are hoping to change that. BioProcess recently received a grant to build a pilot plant in Shenandoah, Iowa. If successful, prototype plants like this one could eventually help make domestic algae power more than a curiosity. —AMBER SASSE


The perfect biofuel?
THE TECHNOLOGY is still experimental, but late last year researchers at Penn State University discovered how to make methane—a main ingredient in natural gas—from the very thing driving climate change: carbon dioxide. The key is microorganisms called methanogens. Engineer Bruce Logan discovered that the organisms produced methane with nothing but water and carbon dioxide when zapped with an electric current. Build a fuel cell around the microbes, and as long as the electricity that feeds into the device comes from a renewable source like wind or solar, the process can provide a carbon-neutral source of combustible fuel.—CATHERINE PRICE

Source of Information : Popular Science July 2009

TECH TO WATCH: hydrokinetic power

Written by Science Knowledge on 7:48 AM

Conventional hydroelectric power (think of the Hoover Dam) provides 7 percent of the electricity in the U.S. But the only way to increase that number without damming more rivers—which causes widespread ecological damage both above and below the dam—is to use nonconventional hydropower sources that capture energy from the movement of waves, rivers and tides.


where we are: 31 GW what we need by 2025: 67 GW

The future of hydropower is taking shape just downstream from a standard hydroelectric dam in Hastings, Minnesota. The power isn’t hydroelectric, though; it’s hydrokinetic, generated from the motion of free-flowing water. Installed this winter in –30° weather and switched on in January, the Houston-based Hydro Green Energy’s pilot plant is the first federally licensed hydrokinetic project in the U.S. Like an underwater wind turbine, it will produce electricity by using the high-velocity current gushing out of an existing hydroelectric dam to turn a 12-foot, three-blade fan. Known as “run-of-river” hydrokinetic, Hydro Green’s technology is similar to turbines that are being used to tap tidal power in Europe, except it’s optimized to work in water flowing in just one direction (tidal turbines use water flowing both in and out). To generate utility-scale power, turbines would be combined into arrays. They could be used in free-flowing rivers too, but coupling them with existing hydroelectric dams eases the Federal Energy Regulatory Commission’s licensing process and offers close access to the electricity grid. Hydro Green says that its technology can create power much more cheaply than a windmill can (4 to 7 cents per kilowatt-hour, compared with 10 cents per kilowatt-hour for wind). The main goal of the plant, which is rated for 100 kilowatts—enough to power 40 homes—is to answer some essential, basic questions: How do you build blades strong enough to withstand the constant flow of water? (Another company, Verdant, installed an experimental hydrokinetic project in New York City’s East River in 2007, only to have the rotors snap days later). How do you balance the presence of a turbine with the local ecosystem— for example, how does a hydrokinetic plant affect the river’s fish population? This spring, Hydro Green embarked on a $500,000 study to determine the impact of the turbines on six species of river fish, and a second, 150-kilowatt turbine will soon be up and running.—HILLARY ROSNER

RIVER RUNNING
Workers attach a walkway
to the nation’s first
commercial hydrokinetic
power turbine, on the
Mississippi River in
Hastings, Minnesota.


Source of Information : Popular Science July 2009

Solar Power

Written by Science Knowledge on 8:46 AM

“Solar power” no longer refers just to chunky photovoltaic panels. A variety of tools for turning sunlight into usable energy—thin-film solar, solar thermal, solar heating, and more—are undergoing a burst of technological acceleration. Whether it’s powering an entire housing development or simply heating your house, taken together, their potential is huge.

where we are : 12.4 GW what we need by 2050: 2,000 GW

A shortage of low-carbon power sources seems absurd when you consider that a nearby star bathes the planet in 85,000 terawatts of energy every year. We just have to capture it.
The Google-funded start-up eSolar has devised a relatively cheap and efficient form of solar power by refining concentrating solar thermal (CST), in which large mirror arrays focus light to create heat and ultimately electricity. Proponents say CST can make solar cost-competitive with coal within a decade. It is “probably the only thing that can be done at a big enough scale to produce terawatts,” says Bill Gross, eSolar’s CEO. At the first eSolar power plant, a five-megawatt facility called Sierra situated northeast of Los Angeles, 24,000 mirrors gather the sunlight falling on 20 acres of land and train it on water-filled boiler units perched on top of towers. This creates temperatures of approximately 850°F, producing steam that turns an onsite turbine to generate electricity.
CST has been around since 1980, but in the 1990s a lack of public interest sent it into hibernation. Now public interest is back in a big way, and CST has awoken with a vengeance. One new megawatt of CST hardware was installed worldwide in 2006; in 2007 there were 100. The Earth Policy Institute projects that the installation of CST worldwide will double every 16 months, from 457 megawatts in 2007 to 6,400 megawatts by 2012. At least 13 plants are in advanced planning stages in the U.S. ESolar’s approach is comparatively cheap because, unlike most of its competitors, which use large, custom-built parabolic mirrors to capture sunlight from all angles, eSolar uses small, flat mirrors, each about the size of a big-screen television. Computerized tracking keeps each mirror focused at the optimal angle throughout the day. The mirrors are easy to manufacture, and it takes just two workers to attach them to relatively light scaffolding on-site. ESolar’s standard 46-megawatt array, which makes enough juice to power about 30,000 homes, occupies only a quarter of a square mile, which will allow the company to avoid the land-use fights that have ensnared other solar companies. Sierra is a demonstration project, but in February eSolar signed a deal to build 11 46-megawatt plants in the Southwest, and it is set to build a full gigawatt’s worth of plants in India. “Efficiency wins in every industry,” Gross says, “and it’s going to win in solar as well.”—DAVID ROBERTS


ELECTRICAL FIELD The Google-funded start-up eSolar uses computer tracking to keep thousands of mirrors like the ones in this illustration focused on boilers sitting atop towers. The light heats the water to 850°F, creating steam that turns a turbine and generates electricity.

Source of Information : Popular Science July 2009

A MAGNETIC MACHINE PLUCKS PATHOGENS FROM BLOOD

Written by Science Knowledge on 8:27 AM

DR. MAGNETO A

MAGNETIC MACHINE PLUCKS PATHOGENS FROM BLOOD



If your uncle says he is getting magnetic therapy, you might feel the urge to tell him to save his money instead for that tinfoil hat to keep the CIA from reading his mind. But if he is being hooked up to Don Ingber’s magnet machine, it just might save his life. Ingber’s device magnetizes microbes and draws them out of the blood. It could save some of the 210,000 Americans— mostly newborns and the elderly—who die sepsis-related deaths every year. Sepsis sets in when bacteria or fungi invade the blood, which can cause organ failure before drugs have time to take effect. “Traditionally, you prescribe antibiotics and pray,” says Ingber, a vascular biologist at Harvard Medical School and Children’s Hospital. His machine operates more quickly.

In lab tests, Ingber’s team mixed donor blood with the fungus Candida albicans, a common cause of sepsis, and added plastic-coated iron-oxide beads, each a hundredth of a hair-width in diameter and covered with antibodies that seek out and attach to the fungus. Next they ran the mixture through the dialysis-like machine, which uses an electromagnet to pull the beads, and any pathogens stuck to them, from blood into a saline solution. The device removes 80 percent of the invaders—enough so that drugs could knock out the rest—in a couple of hours. Ingber will begin animal testing this fall to ensure that the method works in living subjects and doesn’t hurt healthy cells. He might later modify the technique to pull cancer cells from blood or harvest stem cells. “This can sift through a patient’s entire blood volume and pull out the needle in a haystack,” he says. —ALLISON BOND

Source of Information : Popular Science July 2009

THE SHARK FACTORY

Written by Science Knowledge on 11:12 PM

AN ARTIFICIAL UTERUS GIVES AN ENDANGERED SPECIES A SHOT AT SURVIVAL

Overfishing made the grey nurse shark endangered, but it’s the animal’s bizarre, cannibalistic embryos that are making it difficult for the species to rebound. The gestating shark pups need a “time out,” says Nick Otway, a fisheries biologist at Port Stephens Fisheries Institute in Australia. As a last-ditch effort to keep the species from eating itself into extinction, he built an artificial uterus, a souped-up fish tank that will give each unborn baby its own womb.

Female grey nurse sharks have two uteruses, in which embryos play “king of the uterus”: competing for nutrients, with the strong gobbling up weaker kin. The last shark standing in each womb devours any unfertilized eggs during a yearlong gestation, after which the mother gives birth to the two pups. The shark’s long pregnancy and low birth rate—along with people killing it because they mistakenly assumed it is a maneater—have knocked its numbers down to just a few thousand worldwide. And caretakers have had trouble keeping pups born in captivity alive, producing only nine sharks in 20 years. Last September, Otway conducted the first trial of the acrylic uterus with
10-month-old embryos from a pregnant wobbegong shark, a non-cannibalizing, plentiful species whose young develop on the same schedule as the grey nurse’s. He replicated a shark’s uterus by bathing the embryos in 68˚F seawater. After 17 days, the fake womb “gave birth” to six healthy pups. The team plans to experiment with younger wobbegongs and adjust the mixture in the tank to a watery solution rich in urea, sodium and potassium to match the early stages of a wobbegong pregnancy. Before Otway rears grey nurse sharks, his crew will study and duplicate the intrauterine solution found in the mothers. Then he’ll build separate wombs for each embryo. If all goes well with the 10-year project, he could increase a mother’s brood to 20. Otway says he could adapt the device for biologically similar species, but he has no plans to make artificial human uteresus. “That might be possible, but I don’t want to get into it because of the ethical issues,” he says. “I’ll stick with sharks.”—COREY BINNS

Source of Information : Popular Science July 2009

THE FIREPROOF HOUSE

Written by Science Knowledge on 1:01 AM

A NEW SYSTEM COULD STOP RAGING FLAMES FROM BURNING DOWN YOUR HOME

The charred remains of a multimillion- dollar mansion crumbled under Randall Griffin’s work boots. “The entire neighbourhood was burned to ashes,” he says. “There was literally one home left.” Now, less than two years after Griffin surveyed the aftermath of the wildfires that destroyed more than 3,000 homes in Southern California, his group at the Department of Homeland Security’s Science and Technology Directorate is testing a deployable tent that could shield homes from the most ferocious fires. Most houses are in danger well before flames hit their doorstep— burning embers can travel up to a mile in the wind. So DHS teamed with Foster-Miller to adapt a tent typically used to protect military vehicles from chemical attacks into a system that files immediately and send out response crews before things get out of hand.

Better situational awareness is only the beginning. Knowing precisely which areas are at highest risk of fires could transform how we fight them. Voltree Power in Canton, Massachusetts, has developed a shoebox-size sensor that, deflects flames from houses. A year and a few hundred yards of fireproof, rugged nylon cordura later, they produced the SAFE Quick Cover, a rooftop system that rolls out the fabric at the flip of a switch, covering an evacuated house in minutes. (You couldn’t stay in the covered house, because the fire’s heat would still kill you.) “A homeowner could deploy the system on their way out the door,” says Rob Knochenhauer, the lead engineer on the project for Foster-Miller.

Fires that raged through Australia earlier this year killed 173 people, many of whom were caught in the blaze while trying to save their house. “People put themselves in harm’s way because they want a fire truck in front of their home before they will evacuate,” Griffin says. “Quick Cover could save lives while protecting property.”—COREY BINNS planted one per acre, could gather microclimate information, such as spikes in temperature and drops in humidity that signal a nascent fire. In April the Forest Service began field-testing the device, which can run for a decade on voltage generated from the pH imbalance between a tree and soil.

To help deal with the flood of new information, Zimmerman’s team launched the Wildland Fire Decision Support System, an online tool that crunches data in real time, using fire behavior models and weather forecasts. The Forest Service and the National Park Service will use the program to determine whether to attack flames on foot or call in planes to dump fire-suppressant gel.

Even with technological advances in firefighting, perhaps the best way to minimize damage is to recognize that fires play a necessary role in restoring certain ecosystems, and so we should stop building in at-risk areas and use fire-retardant materials, says fire ecologist Max Mortiz of the University of California at Berkeley. Mortiz recently published data predicting that climate change will increase wildfire activity across much of the U.S. “We don’t fight earthquakes and floods—we coexist with them,” he says. “We need to learn to do the same with wildfires.”—COREY BINNS

Source of Information : Popular Science July 2009

Monster fruit

Written by Science Knowledge on 8:28 AM

Nature Genet. doi:10.1038/ng.144 (2008) Fat, juicy tomatoes may be the norm in modern supermarkets; wild tomatoes can be 1,000 times smaller. Biologists at Cornell University in Ithaca, New York, have identified a major genetic determinant of large tomato size that increases the number of female reproductive organs in a tomato flower, and thus the number of compartments in the fruit. The determinant, 6-8-kilobases long, is in a gene called fas, named by Steven Tanksley and his colleagues. The team crossed tomatoes of varying girth and mapped the genetic region that conferred the tomatoes’ compartment number. The insertion in fas is probably a mutation that occurred during tomato domestication; it was not present in 30 lines of the wild tomato from which domestic tomatoes are thought to descend.


About Me

In its broadest sense, science (from the Latin scientia, meaning "knowledge") refers to any systematic knowledge or practice. In its more usual restricted sense, science refers to a system of acquiring knowledge based on scientific method, as well as to the organized body of knowledge gained through such research.

Fields of science are commonly classified along two major lines: natural sciences, which study natural phenomena (including biological life), and social sciences, which study human behavior and societies. These groupings are empirical sciences, which means the knowledge must be based on observable phenomena and capable of being experimented for its validity by other researchers working under the same conditions.


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