Physicists later realized that the absolute temperature of a gas is related to the average energy of its particles.
which particles have no energy at all, and higher temperatures correspond to higher average energies. However, by the 1950s, physicists working with more exotic systems began to realise that this isn't always true:
Technically, you read off the temperature of a system from a graph that plots the probabilities of its particles being found with certain energies.
Normally, most particles have average or near-average energies, with only a few particles zipping around at higher energies.
In theory, if the situation is reversed, with more particles having higher, rather than lower energies, the plot would flip over
and the sign of the temperature would change from a positive to a negative absolute temperature,
electrically charged particles, corralled into separate doughnut-shaped rings by Earth s magnetic field. The outer ring orbits at a distance of some 10,000-60,000 kilometres above Earth,
and encircles an inner band of even more energetic particles, roughly 100-10,000 kilometres above Earth.
narrow belt of charged particles sandwiched between the inner ring and a now highly eroded outer ring."
however, and Baker and his team now attributes its creation to an interplanetary shock wave#a travelling outburst of solar-wind particles from the Sun#that has been detected by other craft.
"It s a new way of trying to get the immune system to prevent phagocytosis of drugs or particles.
when a proton binds to the MATE protein at a spot on its extracellular side, one of the protein's segments switches from a straight to a bent shape to push any nearby foreign molecule out of the cell1."
"They have a direct mechanism of how the protons change the shape of the cavity.
The map even shows that the number of neutrino flavours permeating the cosmos will probably remain at three#had there been a fourth,
particles such as protons and electrons formed from the cauldron of proto-matter, and photons began to bounce around like pinballs.
It was only 380,000#years later, when the charged plasma cooled into neutral atoms, that those photons could fly freely.
Today they make up the CMB, and carry with them an imprint of the quantum fluctuations that roiled the inflationary Universe.
That transition allowed photons to travel unimpeded through space, in a pattern that carried the echoes of inflation.
Those photons are still out there today as a dim glow of microwaves with a temperature of just 2. 7 kelvin.
Researchers have developed a microscopic device that can detect the ebb and flow of electrons within an alga as it photosynthesizes.
The device is known as a single-electron transistor, and its inventors hope that it could be used to measure the performance of biofuel-producing organisms,
for example#a single electron can switch the transistor on, amplifying a tiny signal into a much larger current in the main circuit.
The first single-electron transistors were built in the late 1980s1, but most require very low temperatures#otherwise, the electrons gather enough energy to tunnel through the semiconductor,
and current leaks through the switch. A handful work at room temperature (by using carbon nanotubes to detect electrons
for example2), but they cannot operate in water#a serious obstacle to using such devices in living organisms.
In 2008, materials scientist Ravi Saraf at the University of Nebraska-Lincoln and his colleagues built a room-temperature single-electron transistor using a different approach3.
But if an electron settles on a defective nanoparticle it makes it slightly easier for current to flow,
"That s something really new, says Simon. The cells sit on the surface of the gold#nano particles,
Shining a light on the cells triggers a cascade of biochemical reactions that transfer electrons along a chain of molecules#and switches the transistor on.
#Tau Associated MAPT Gene Increases Risk for Alzheimer's disease A international team of scientists, led by researchers at the University of California,
San diego School of medicine, has identified the microtubule associated-protein protein tau (MAPT) gene as increasing the risk for developing Alzheimer disease (AD).
the role of the tau-associated MAPT gene is said still unclear Rahul S. Desikan, MD,
and more likely to experience increased brain atrophy than non-carriers. his study demonstrates that tau deposits in the brains of Alzheimer disease subjects are not just a consequence of the disease,
since Alois Alzheimer time that both plaques (with amyloid) and tangles (of tau) are key features of Alzheimer pathology,
Until this year no one had shown convincingly that the MAPT (tau) gene altered the risk of AD and this,
combined with the greater ease of imaging amyloid in life, lead some researchers to postulate that tau changes were secondary to amyloid changes.
The recent association of genetic variation in the MAPT gene with AD risk and the emerging availability of tau imaging are now leading to a recognition that perhaps tau changes are key in the pathophysiologic pathway of AD
This is controlled by balancing the activity of protein umpsthat push protons into endosomes to increase their acidity with that of protein eaks
like NHE9, that remove protons. Rao says: ndosomes are like buckets of water that have to be kept full despite the leaks in them.
which pump out too many protons (orange), changing the endosomesacidity and slowing their hipping speed.
causing endosomes to leak too many protons and become too alkaline. This slows down the hipping rateof cancer-promoting cargo and leaves them on the cell surface for too long.
Secondly, the particles can be triggered by an outside magnetic field to produce an electric field when adjacent to individual neurons.
and pollution particles in the sky left behind by jet aircraftctually are signs of a clandestine government effort to modify the weather.
#'Edible Barcodes'Help Fight Counterfeit Drugs Who knew that the answer to fighting the trillion-dollar global counterfeit drug problem rested in a particle the size of a speck of dust?
Within each of the tiny particles is an elaborate nanopore structure think of it as a series of microscopic holes within a thin membrane,
Wuh said the idea of tiny microscopic particles containing data about a drug is farfetched no more than someone 20 years ago saying that a person would have a upercomputer the size of his palm. ut,
000 cubic feet of air--42 percent of which is made of carbon particles. One tower alone is capable of cleaning 123 million cubic feet of clean air per day.
Holding up a bag of pollution particles in this video, he explains that it hard to believe that we accept this pollution as waste
but a more refined approach might allow researchers to standardize the size of diamond particles
Another common approach to levitation involves filling an object with iron oxide particles. But that would be toxic to living cells.
They laced the fluid with particles of gadolinium a rare-earth metal that is highly magnetic and sometimes given to patients to increase contrast in an MRI.
The magnetic field is shaped to pull the gadolinium downward so metal particles push the cells upward,
#Strange new subatomic particles discovered at atom smasher Exotic subatomic particles made up of five quarks that physicists briefly thought they had discovered back in 2003 now finally appear to be in the bag.
who claim to have found conclusive evidence for the existence of so-called pentaquarks within the debris of high-energy proton collisions.
The discovery has filled a big hole"in the theory that describes how matter is built up from the fundamental particles known as quarks,
describes how the protons and neutrons that make up atomic nuclei are composed themselves of three quarks and how other particles known as mesons are made from pairs of quarks and their antimatter counterparts, antiquarks.
However, Gell-Mann's scheme also pointed to the existence of pentaquarks, made up of four quarks and an antiquark.
The lack of any evidence for such particles over the past 50 years says Wilkinson,
"didn't throw the theory into disrepute but was becoming increasingly troublesome.""To catch the elusive prey,
Wilkinson and colleagues studied the decay of"lambda-b"particles created by protons colliding within LHCB.
They measured the combined energy of two of the decay products proton and a meson known as J/Psi,
which consists of a"charm quark and antiquarknd then totted up how many times they recorded each energy value across the thousands of collisions they studied.
They found that the number of pairings with a certain energy little under five times the mass of the protonas far higher than would be expected by chance.
The researchers concluded that that was the mass of a fleeting"charmonium"pentaquark containing two up quarks, one down quark, one charm quark,
and one anticharm quark. LHCB collected the data back in 2011 and 2012, but Wilkinson's team held back from announcing their discovery to avoid the fate of those who had made the earlier claims of pentaquark sightings.
the LHCB collaboration made use of data showing not only the energy of the particles produced in the CERN collisions but also their directions.
For comparison, a proton weighs in at 0. 94 Gev. The research has been uploaded to the arxiv server
"They appear to have found strong evidence for a'heavy quark'pentaquark state, "says Ken Hicks of Ohio University.
whether all five quarks are bound tightly together inside the new particle, or whether instead three quarks group together as they do inside protons
and neutrons and the other two form a separate meson bit like two atoms combining to form a molecule.
Wilkinson says that because pentaquarks might be formed inside collapsing stars, their discovery might tell us more about what stars are composed of
"Now that we know nature allows five quarks to be bound together, it would be very strange indeed
if just this set of quarks is allowed to coexist in this manner, "he says.""There should be many others.
or cathode, where oxygen molecules pick up extra electrons. These oxygen ions then travel through the membrane to the positively charged anode.
Additional radio signals cause the protons in your body's liquids to resonate with the magnetic field
The pulses make protons in the body spin in a precise way that sends signals that can be interpreted as the location and density of fluid in the bones and muscle.
The effect may be the first time that a lab-based black hole has created Hawking particles in the same way expected from real black holes.
But in 1974 Stephen Hawking of the University of Cambridge predicted they should emit a faint glow of particles now known as Hawking radiation.
but fizzes with pairs of particles and their antimatter counterparts. Normally these pairs annihilate each other
of which trapped photons using laser pulses in a fibre optic-cable cable. The team claimed this had produced Hawking radiation
The horizons create pairs of particles of sound or phonons. One phonon escapes the horizon
The device zaps water with electricity to release oxygen then a silicon-based chemical mediator dissolved in the water mops up stray protons and electrons.
When the hydrogen is needed putting the mediator in contact with a platinum catalyst allows those electrons
and protons to recombine to make hydrogen gas. The whole process uses a single whack of power and patchy renewable energy will suffice for this says Cronin.
An unexpected pattern has been glimpsed in the solar wind the turbulent plasma of charged particles that streams from the sun. It offers clues for handling plasmas that roil inside nuclear fusion reactors On earth.
Composed of charged particles such as protons and electrons the solar wind streams from the sun and pervades the solar system.
Its flow is turbulent containing eddies and moving at different speeds in different directions. It was thought that this turbulence was similar to that in a fluid behaving like mixing ocean currents
when the movement of the wind's particles is perpendicular to the sun's magnetic field they resemble a fluid with sections that are smooth interrupted by bursts of violence.
But when the particles move in parallel with the field lines they behave very differently with the turbulence evenly spread like crinkly mountains that extend as far as the eye can see (see diagram.
or align the electromagnetic fields of photons they came into contact with in the infant universe.
Those photons which have been travelling through space ever since appear in every direction in the sky as the cosmic microwave background (CMB) radiation.
But other things apart from gravitational waves such as dust can emit polarised photons. To minimise the chances of this effect causing a false signal the BICEP 2 team pointed their telescope at a patch of sky far away from the Milky way's dusty disc.
If the aligned dust contains iron the particles'slight vibrations due to their own heat would produce polarised microwave radiation says Mertsch.
if you take the dust into account along with emissions from charged particles in the galaxy
which protects us from the bulk of the solar wind a stream of high-energy particles constantly flowing from the sun
Charged particles can flow along these lines into Earth's atmosphere leading to dazzling auroras as well as geomagnetic storms that can wreak havoc on navigation systems and power grids.
In January 2013 GPS sensors on the ground mapped electrons in the upper atmosphere and saw a tendril of increased electron density curling away from the north pole indicating that a plume of plasma was veering off towards the sun. At the same time three of NASA's THEMIS spacecraft
which are designed to study solar storms crossed through the magnetic boundary during the event. The craft saw a 100-fold increase in the number of electrons at the boundary
which would probably have been deposited by the plume. For the first time we were able to monitor the entire cycle of this plasma stretching from the atmosphere to the boundary between Earth's magnetic field
Mirin made a nanowire detector that operates at-270 C. This boosted the number of photons it received each second by two orders of magnitude compared with regular detectors.
#Boxy Cubesats get a propulsion boost in new space race Tiny liquid volcanoes that spray beams of charged particles could make space history next year.
But we also know that the sun pumps out a constant stream of charged particles called the solar wind
and pick up the newly charged particles effectively sweeping them away. Earth is protected from the solar wind by a relatively strong global magnetic field
which repels charged particles from the sun explains Nick Schneider of the Laboratory for Atmospheric
Choreographed high-power lasers or electron beams can fuse and sculpt metal powders into high-performance machine parts.
At the same time a stream of particles blowing out from the sun the solar wind inflates a bubble of plasma around the solar system called the heliosphere Astronomers have assumed long that the sun's motion through the galaxy squashes
when charged particles from the solar wind collide with other charged particles in the outer heliosphere Some of these neutral atoms are bounced back towards us.
if we were to look straight down the length of the tail from front to back we would see particles clustered into four distinct lobes like a four-leaf clover (see image above right).
Two opposing lobes on the vertical plane consist of fast-moving particles while the two lobes on the horizontal plane consist of slower-moving particles (watch a NASA video of the tail in action).
The four lobes might be a reflection of solar activity at the time the particles left the sun says IBEX principal investigator David Mccomas. The particles took a few years to reach the tail
so they were born when the sun was minimally active. Around solar minimum you get slow solar wind around low to mid-latitudes from the sun
. But he expected this would create more of a solid horizontal band of slow particles across the tail not the odd lobes.
At solar maximum the bands of slow and fast particles streaming away from the sun break down so the tail may change its shape
The magnetic field of the heliosphere protects us from the bulk of these galactic high-energy particles. But some manage to impinge on our solar system
#Tabletop accelerator shoots cheap antimatter bullets Make way for the antimatter gun. A tabletop device just 10 square metres in size can spit out energetic bursts of positrons as dense as those kicked out by the giant particle-factories at CERN.
Each positron-packed bullet lasts for just a fraction of a second so don't expect to fill the tank of your antimatter engine any time soon.
Instead the smaller cheaper machine might help labs around the world study deep-space objects such as powerful radiation jets squirted out by black holes.
Antiparticles have the same mass as their ordinary particle counterparts but carry an opposite charge and spin.
The particles annihilate on contact with ordinary matter vanishing in a puff of energy which makes it difficult to produce
Huge machines at particle physics labs such as CERN near Geneva Switzerland have been churning out antimatter for over a decade.
Instead Gianluca Sarri at Queen's university Belfast UK and colleagues used rapid laser bursts to make positrons in their smaller budget device.
The laser pulse ionises inert helium gas generating a stream of high-speed electrons. This electron beam is directed at a thin metallic foil
so that it crashes into metal atoms releasing a jet of electrons and positrons. These particles are separated into two beams with magnets (Physical Review Letters doi. org/m2n.
The team call their device an antimatter gun because the bursts of positrons last just 30 femtoseconds (quadrillionths of a second).
Despite their short duration the beams contain a quadrillion positrons per cubic centimetre says Sarri meaning they are comparable in density to the ones made at CERN.
In 2008 scientists at the Lawrence Livermore National Laboratory in California produced large quantities of antimatter by directing an extremely powerful laser at a tiny gold disc.
Sarri says his setup is much more practical and cheaper: They needed much stronger lasers
and those lasers are expensive. Also they produced streams of positrons that were extremely broad
whereas our jet is a hundred times narrower and remains pencil-like as it propagates he adds.
This is similar to the powerful streams of matter-antimatter observed outside pulsars and black holes. CERN physicist Niels Madsen notes though that the tabletop device has limitations.
It only makes relatively light particles like positrons whereas to make an anti-atom you also need antiprotons
which are almost 2000 times more massive. For now he says making heavier antiparticles is not doable in a small lab in a cheap fashion.
Nor does the smaller machine address the problem of antimatter storage. To hold antimatter stable it must be chilled
and the tabletop method makes searing-hot beams of particles moving at near light speed. As an alternative says Sarri the beams can be used to mimic the way particle fountains from black holes
and pulsars shoot through and interact with gases in the interstellar medium creating mini versions of these enigmatic astrophysical phenomena in the lab for the first time.
This article will appear in print under the headline Antimatter bullets get fast and chea a
#China inches closer to building its own space station Update 11 june 2013: The China National Space Administration successfully launched its Shenzhou-10 mission to low Earth orbit at 0938 GMT today.
The Long March 2f rocket lifted off flawlessly from the Jiuquan space centre in Mongolia's Gobi desert
and headed towards the fledgling spacefaring nation's space station Tiangong 1 around which it is expected to test manoeuvres before docking for a 15-day stay on orbit.
If you can grow large particles they will disappear very quickly says Nienke van der Marel of Leiden Observatory in The netherlands.
It means there must be some mechanism that is keeping the large dust particles there because they're not drifting inwards.
and minerals that could act like batteries allowing electrons to flow and bring energy to any potential organisms.
and gained electrons and so could have acted as microbial energy sources. All these clues point to ancient Mars hosting neutral slightly salty liquid water that could have supported primitive life.
and friction the pulverised particles were sent up the screw-shaped drill bore and into a receptacle where they were sifted
Such particles could help scientists to track specific molecules produced in the body monitor a tumor s environment
In a paper appearing in the Nov 18 issue of Nature Communications the researchers demonstrate the use of the particles which carry distinct sensors for fluorescence
Wherever there is a high concentration of Vitamin c the particles show a strong fluorescent signal but little MRI contrast.
Future versions of the particles could be designed to detect reactive oxygen species that often correlate with disease says Jeremiah Johnson an assistant professor of chemistry at MIT and senior author of the study.
Dual actionjohnson and his colleagues designed the particles so they can be assembled from building blocks made of polymer chains carrying either an organic MRI contrast agent called a nitroxide
For this study they created particles in which 99 percent of the chains carry nitroxides and 1 percent carry Cy5. 5. Nitroxides are reactive molecules that contain a nitrogen atom bound to an oxygen atom with an unpaired electron.
Nitroxides suppress Cy5. 5 s fluorescence but when the nitroxides encounter a molecule such as Vitamin c from
which they can grab electrons they become inactive and Cy5. 5 fluoresces. Nitroxides typically have a very short half-life in living systems
The researchers found that their imaging particles accumulated in the liver as nanoparticles usually do.
The mouse liver produces Vitamin c so once the particles reached the liver they grabbed electrons from Vitamin c turning off the MRI signal
These particles could also be used to evaluate the level of oxygen radicals in a patient s tumor which can reveal valuable information about how aggressive the tumor is.
The system uses a pair of linked particles with magnetic properties. In the presence of a magnetic field the paired particles begin to tumble across a surface with first one particle
and then the other making contact in effect walking across the surface. So far the work has been carried out on a model cell surface on a functionalized microscope slide
The particles naturally migrate toward high-friction regions where they could then be induced to interact with a surface by active molecules attached to them.
The use of a pattern that localizes particles may be useful to enhance the localization of particles with specific properties.
#Nanoparticles get a magnetic handle A long-sought goal of creating particles that can emit a colorful fluorescent glow in a biological environment
And finally the particles could have a coating of a bioreactive substance that could seek out
For one thing he says such particles have been too large to make practical probes of living tissue: They ve tended to have wasted a lot of volume Bawendi says.
In addition previous efforts were unable to produce particles of uniform and predictable size which could also be an essential property for diagnostic or therapeutic applications.
The new method produces the combination of desired properties in as small a package as possible Bawendi says which could help pave the way for particles with other useful properties such as the ability to bind with a specific type of bioreceptor or another
The magnetic particles cluster at the center while fluorescent particles form a uniform coating around them.
That puts the fluorescent molecules in the most visible location for allowing the nanoparticles to be tracked optically through a microscope.
Initially at least the particles might be used to probe basic biological functions within cells Bawendi suggests.
As the work continues later experiments may add additional materials to the particles coating so that they interact in specific ways with molecules or structures within the cell either for diagnosis or treatment.
Melanie Gonick/MIT The ability to manipulate the particles with electromagnets is key to using them in biological research Bawendi explains:
The tiny particles could otherwise get lost in the jumble of molecules circulating within a cell.
A silica coating on the particles allows additional molecules to attach causing the particles to bind with specific structures within the cell.
which particles can be ejected. Higher currents thus promise more-efficient manufacturing and more-nimble satellites.
which is broken into particles by chemical reactions with both the substrate and the environment. Then they expose the array to a plasma rich in carbon.
The nanotubes grow up under the catalyst particles which sit atop them until the catalyst degrades.
which are located in the cell membrane and pump potassium in and protons out. Industrial relevancebefore yeast begin their work producing ethanol the starting material usually corn must be broken down into glucose.
and bacteriophage particles that bind to the bacteria and inject the genes. Both of these carriers successfully spread the CRISPR genes through the population of drug-resistant bacteria.
what counts as infected red blood cells versus some dust particles stuck on the plate. It really takes a lot of practice he says.
but if another magnetic particle such as hemozoin is present this synchrony is disrupted through a process called relaxation.
The more magnetic particles are present the more quickly the synchrony is disrupted. What we are trying to really measure is how the hydrogen s nuclear magnetic resonance is affected by the proximity of other magnetic particles Han says.
For this study the researchers used a 0. 5-tesla magnet much less expensive and powerful than the 2
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