Physics Tricks
The Physical Approach to Human Development
Monday, 6 February 2017
EXCLUSIVE: The "lab-on-a-chip" technology built with one cent
The inexpensive lab-on-a-chip technology has the potential to enhance diagnostic capabilities around the world, especially in developing countries.
Researchers at the Stanford University School of Medicine have developed a way to produce a cheap and reusable diagnostic "lab on a chip" with the help of an ordinary inkjet printer.
At a production cost of as little as 1 cent per chip, the new technology could usher in a medical diagnostics revolution.
Due to inferior access to early diagnostics, the survival rate of breast cancer patients is only 40 percent in low-income nations—half the rate of such patients in developed nations. Other lethal diseases, such as malaria, tuberculosis and HIV, also have high incidence and bad patient outcomes in developing countries. Better access to cheap diagnostics could help turn this around, especially as most such equipment costs thousands of dollars.
"Enabling early detection of diseases is one of the greatest opportunities we have for developing effective treatments," Esfandyarpour said. "Maybe $1 in the U.S. doesn't count that much, but somewhere in the developing world, it's a lot of money."
A combination of microfluidics, electronics and inkjet printing technology, the lab on a chip is a two-part system. The first is a clear silicone microfluidic chamber for housing cells and a reusable electronic strip. The second part is a regular inkjet printer that can be used to print the electronic strip onto a flexible sheet of polyester using commercially available conductive nanoparticle ink.
"We designed it to eliminate the need for clean-room facilities and trained personnel to fabricate such a device," said Esfandyarpour, an electrical engineer by training. One chip can be produced in about 20 minutes, he said.
Designed as a multifunctional platform, one of its applications is that it allows users to analyze different cell types without using fluorescent or magnetic labels that are typically required to track cells. Instead, the chip separates cells based on their intrinsic electrical properties: When an electric potential is applied across the inkjet-printed strip, cells loaded into the microfluidic chamber get pulled in different directions depending on their "polarizability" in a process called dielectrophoresis. This label-free method to analyze cells greatly improves precision and cuts lengthy labeling processes.
The tool is designed to handle small-volume samples for a variety of assays. The researchers showed the device can help capture single cells from a mix, isolate rare cells and count cells based on cell types.
The technology has the potential to not only advance health care, but also to accelerate basic and applied research. It would allow scientists and clinicians to potentially analyze more cells in shorter time periods, manipulate stem cells to achieve efficient gene transfer and develop cost-effective ways to diagnose diseases, Esfandyarpour said. The team hopes the chip will create a transformation in how people use instruments in the lab. "I'm pretty sure it will open a window for researchers because it makes life much easier for them—just print it and use it,"
Sunday, 21 September 2014
Perovskite is offering new hope for versatile and efficient solar cells to meet our future energy needs.
The energy
needs of the world could all, in principle, be fulfilled by one single source
-- the sun. There are challenges in making this a reality, however:
affordability first, and finding a way to capture this energy efficiently to
turn it into electricity.
Recently, a
new material known as perovskite has seen the light of day and within just a
few years it has started rivaling the efficiency of traditional photovoltaic
solar cells, which currently maxes out at roughly 20 percent. This is the
amount of solar energy that gets converted into electricity and the higher this
is, the more we meet our energy needs. Over 80 percent of today's photovoltaics
are made from crystalline silicon, but the high expense of both their
production and installation means we are in need of alternatives.
Perovskite
is a mineral found in the Earth's mantle, named after Russian mineralogist Lev
Perovski. Since 2009, it has caught the attention of researchers across the
globe, including those at Oxford University and the Federal Institute of
Technology in Lausanne (EPFL).
Graetzel
discovered how perovskite works and he's helping develop new solar cells as
well as potential ways to add on to existing ones: "You can put perovskite
on top of traditional silicon cells to make them more efficient," he says.
"This is not an expensive process and can become an attractive application
for mainstream solar panels."
Stability
tests are still needed as this magical material is sensitive to water and high
temperatures: "This is all being examined now. I'm optimistic and sure
this can be tackled. It's an exciting time".
Perovskite
solar cells may be the ones to watch, but the search for the most efficient,
affordable and usable form of solar energy is a diverse battlefield.
Saturday, 20 September 2014
Mental exercise in blindness reflects the reality of our universe
Take a look around you, and in your mind's eye, randomly wipe out
all but a small fraction of what you can see. Pretend the vast rest of reality
is there but invisible.
You'd probably like a
device that helps you see much more of it.
Scientists working at
CERN, the European Organization for Nuclear Research, have made some progress
in that direction with the Alpha Magnetic Spectrometer (AMS), which has been
riding aboard the International Space Station since 2011.
Physicists believe that mental exercise in blindness reflects
the reality of our universe, only about 4% of which manifests as the kind of
matter and energy we can perceive.
More than 70% consists
of so-called dark energy, physicists say, and more than 20% is dark matter,
neither of which humans can directly detect so far.
But scientists feel
certain it must exist, partly because of the gravity it exerts on the visible
universe.
Tuesday, 16 September 2014
What makes some people capable of amazing perseverance?
In September 2013, at age 64, distance swimmer Diana Nyad achieved a goal she’d been chasing for more than 35 years:
She swam from Cuba to Florida, 110 miles, without a shark cage to protect her. During the 53-hour swim, she paddled through swarms of venomous box jellyfish and vomited repeatedly from swallowing saltwater.
Her entire body trembled from the cold. But she forged on, resolute in her determination to complete one stroke after another.
She swam from Cuba to Florida, 110 miles, without a shark cage to protect her. During the 53-hour swim, she paddled through swarms of venomous box jellyfish and vomited repeatedly from swallowing saltwater.
Her entire body trembled from the cold. But she forged on, resolute in her determination to complete one stroke after another.
Monday, 15 September 2014
A good breeze
It might not be something you think much about, but a well-ventilated room is important for your health. “There’s a lot of studies that have been done over the last 20-30 years that say people who work or study in naturally ventilated buildings perform better,” says Ben Hughes, a Lecturer in Building Physics from the University of Leeds. Free-flowing air removes dust and dirt as well as reducing the amount of CO2 and excess moisture in your immediate atmosphere and makes for a much more pleasant environment. “As air passes over your skin it gives you a sensation of being comfortable,” says Ben.
But moving air also removes heat, so a well-ventilated building needs good heating – and that comes at a price. Most commercial buildings use mechanical heating ventilation and air conditioning (HVAC) systems to control the temperature and airflow in a room. But “depending on where in the world you are, between 40-60% of a building’s energy consumption is from the HVAC systems,” says Ben.
One way to tackle this intensive energy use is to design and build super-economical airtight houses. This is the idea behind the Passivhaus standard; a house that doesn’t need heating but relies instead on heat from the people living in the house and items such as the cooker and lights.
So designers are now taking inspiration from the old way of ventilating houses and buildings, so-called natural ventilation.
But moving air also removes heat, so a well-ventilated building needs good heating – and that comes at a price. Most commercial buildings use mechanical heating ventilation and air conditioning (HVAC) systems to control the temperature and airflow in a room. But “depending on where in the world you are, between 40-60% of a building’s energy consumption is from the HVAC systems,” says Ben.
One way to tackle this intensive energy use is to design and build super-economical airtight houses. This is the idea behind the Passivhaus standard; a house that doesn’t need heating but relies instead on heat from the people living in the house and items such as the cooker and lights.
So designers are now taking inspiration from the old way of ventilating houses and buildings, so-called natural ventilation.
Sunday, 14 September 2014
A bolt of lightning has enough energy to toast 100,000 slices of bread.
It's an awful lot of toast, but then a typical lightning bolt isn't short on energy with over five billion Joules. This means that one typical strike could power a 1000 Watt, two slice toaster for 84,000 minutes in which time you could make around 100,000 slices of toast.
Thunderstorms are an amazing natural spectacle, but even more amazing is the fact that we still don't totally understand the processes which create lightning. What we do know is that lightning is a discharge of the static electricity that builds up in clouds in certain weather conditions.
You've probably noticed that thunderstorms often happen on summer afternoons when the ground is warm and the air is humid. As the warm, humid air rises and meets cooler conditions higher up, water condenses out of the air to form clouds. The condensed water droplets then start to fall and collide with the warm air that is still rising.
All these little collisions give the water droplets a charge and for some, as yet unknown, reason the positively charged droplets find their way to the top of the cloud whilst the negatively charged droplets fall to the bottom.
This separation of charge creates an electric field within the cloud which grows stronger as the charges build up and induces a positive charge in the ground directly below the cloud. Zigzagged.
Air is normally a very good electrical insulator, but when the electric field becomes strong enough it ionises the air, separating it into negative and positive ions, and producing a conductive path between the cloud and ground. But the ionisation of the air isn't uniform and zigzagged "step leaders" start to appear from the cloud following the various conductive paths. At the same time positive streamers start reaching up from the ground, waiting for the step leaders to connect to them. Once a complete path is formed, there's a deafening crack and the lightning reaches the ground.
With five billion Joules of electrical energy being discharged, the surrounding air becomes hotter than the surface of the Sun. We see this as a white flash and hear it as rumbles of thunder as the air rapidly expands.
Why We Yawn?
Researchers are starting to unravel the mystery surrounding one of the most common behaviors: the yawn.
WSJ’s Jonathan Rockoff and evolutionary psychologist Dr. Andrew Gallup explain new studies suggesting it’s a way of keeping your brain sharp. Science has disproved the theory that it’s the body’s way of sending oxygen to your brain when deprived. Says Rockoff, one of the leading theories is that yawning is a “cranial air conditioner.”
In times of stress and anxiety, we experience a slight rise in brain temperature. So the body steps in to cool it off.
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