Tag Archives: molecule

What are the strong chemical bonds?

Everything around you is made of chemicals. And that’s only possible because those chemicals interact and bind together. Exactly how and why they do this depends on their nature but, in general, there are two kinds of interactions that keep them close: “primary” (or ‘strong’) and “secondary” (or weak) interactions.

Image credits Thor Deichmann.

These further break down into more subcategories, meaning there’s quite a lot of ground to cover. Today, we’ll be looking at the strong ones, which are formed through the transfer of electrons or electrostatic attraction between atoms.

As we go forward, keep in mind that atoms interact in order to reduce their energy levels. That’s what they get out of bonding to other chemicals, and they will do so until they find a bond-mate which will bring perfect balance to their lives; kinda like people do.

An atom’s stable configuration, the state all atoms tend towards, is known as its noble gas configuration. Noble gases make up the last column on the periodic table’s rightmost side, and they’re extremely or completely non-reactive chemically (they don’t need to interact because they have internal equilibrium).

Strong bonds are the most resilient ties atoms or molecules can forge with their peers. The secret to their strength comes from the fact that primary interactions are based on an atom’s valence. The valence number signifies how many electrons zipping around an atom’s core can be ‘shared’ with others. The overwhelming majority of a substance’s chemical behavior is a direct product of these electrons.

Covalent bonds

The first type of strong interactions we’ll look at, and the most common one, is the covalent bond. The name, “co-valence” sums up the process pretty well: two atoms share some or all of their valence electrons, which helps both get closer to equilibrium. This type of bond is represented with a line between two atoms. They can be single (one line), double (two lines), or triple (three lines).

File:Covalent Organic Frameworks (space-filling diagram).jpg
Covalent bonds are especially important in organic chemistry. Image via Wikimedia.

In essence, what happens inside a covalent bond is that you have an atom starved of electrons (positively charged) and one who has too many electrons (negatively charged). Neither of them wants to keep going on like that because their internal imbalance of electrical charges makes them unstable. When put close to each other, they will start behaving like a single ‘macroatom’ — their electrons will start orbiting around both.

These shared orbits are what physically keeps the atoms together. The atom with too many electrons only ‘has’ them for half the time, and the one with too few gets to have enough half the time. It’s not ideal, but it’s good enough and it requires no changes to the structure of the atom (which is just dandy if you ask nature).

Things get a bit more complicated in reality. Electrons don’t zip around willy-nilly, but need to follow certain laws. These laws dictate what shape their orbits will take (forming ‘orbitals’), how many layers of orbitals there will be and how many electrons each can carry, what distance these orbitals will be from the nucleus, and so on. In general, because of their layered structure, only the top-most orbitals are involved in bonding (and as such, they’re the only ones giving elements their chemical properties). Keep in mind that orbitals can and do overlap, so exactly what ‘top-most’ means here is relative to the atom we’re discussing.

Orbitali, Lipire, Atom, Moleculă, Legarea Covalentă
A 3D rendering of electron orbitals. Image via Pixabay.

But to keep it short, covalent bonding involves atoms pooling together their free electrons and having them orbit around both, using each other’s weakness to make the pair stronger.

Covalent bonds are especially prevalent in organic chemistry, as it is the preferred way carbon bonds to other elements. The products they form can exist in a gas, liquid, or solid state, whereas the following two types can only produce solid substances.

Ionic bonds

Next are ionic bonds. Where covalent bonds involve two or more atoms sharing electrons, ionic bonds are more similar to donations. This type of chemical link is mediated by an electrostatic charge between atoms (negatively charged particles attract positively-charged ones). The link is formed by one or more electrons going from the donor to the receiver in a redox (oxidation-reduction) reaction; during this type of reaction, the atoms’ properties are changed, unlike in covalent bonds. Ionic bonds generally involve a metal and a nonmetal atom.

File:Sodium chloride - crystals.jpg
Table salt crystals. Salts are formed from ionic bonds. Image via Wikimedia.

Table salt is a great example of a compound formed with ionic bonds. Salt is a combination of sodium and chlorine. The sodium atom will cede one of its electrons to the chlorine, which will make them hold different electrical charges; due to this charge, the atoms are then strongly drawn together.

It again ties into equilibrium. Due to the laws governing electron orbitals, there are certain configurations that are stable, and many others that are not. At the same time, atoms want to achieve electrostatic neutrality, as well. In an ionic bond, an atom will take an increase in its electrostatic energy (it will give or take negative charge) to lower its overall internal imbalance (by reaching a stable electron configuration) because that’s what lowers its energy the most.

Covalent bonds for the most part take place between atoms with the same electrostatic properties, and there’s no direct transfer of electrons because that would increase the overall energy levels of the system.

Ionic bonds are most common in inorganic chemistry, as they tend to form between atoms with very different electrostatic properties and (perhaps most importantly) ionic compounds are always soluble in water. However, ionic compounds such as salts do have a very important part to play in biology.

The main difference between ionic and covalent bonds is how the atoms involved act after they link up. In a covalent bond, they are specifically tied to their reaction mates. In an ionic bond, each atom is surrounded by swarms of atoms of opposite charge, but not linked to one of them in particular. Atoms with a positive charge are known as cations, while those with a negative charge are anions.

Another thing to note about ionic bonds is that they break if enough heat is applied — in molten salts, the ions are free to move away from each other. They also quickly break down in water, as the ions are more strongly attracted to these molecules than each other (this is why salt dissolves in water).

Metallic bonds

File:CrystalGrain.jpg
Microstructure of VT22 steel (titanium wrought alloy) after quenching. Image via Wikimedia.

If the name didn’t give it away, this type of chemical bond is the hallmark of metal and metallic alloys. It’s not the only type of bond that they can form, even between pure metals, but it’s almost always seen in metals.

Chemically speaking, metals are electron donors — they need to shed electrons to reach equilibrium. Because of the nature of these atoms, their electrons can move around between atoms, forming ‘clouds’ of electrons. These detached electrons are referred to as being ‘delocalized’.

This type of bond shares properties of both ionic and covalent bonds. In essence, every metal atom needs to give away electrons to be stable (thus behaving like a cation). But because it’s surrounded by other metal atoms (meaning other cations), there’s nobody who wants to accept that electrical charge. So the electrons get pooled together and everyone gets to have them some of the time (thus forming a covalent bond). You can think of it as an ionic bond where the atomic nuclei form the cations and the electrons themselves the anions. Another way to look at it, although this is more of an abstraction used to illustrate a point, is that all the atoms involved in a metallic bond share an orbital.

Keep in mind that this ‘sea of electrons’ theory is a model of the process — it’s oversimplified and not a perfect representation of what’s actually going on, but it’s good enough to give you a general idea of how metallic bonds work.

Because metallic bonds share properties of both ionic and covalent bonds they create crystalline bonds (like salts) while still remaining malleable and ductile (unlike most other crystals). Most of the physical properties we seek in metals are a direct product of this structure. The cloud of delocalized electrons acts as a binder, holding the atoms together. It also acts as a cushion, preventing mechanical shock from fracturing the structure. When blacksmiths hammer iron or steel, they rearrange the atomic cores. Electrons can still move around them, like water around the rocks in a stream, and help hold everything together during the process.

Metallic bonds have the lowest bond energy of the types we’ve seen today — in other words, they’re the most stable.


Chemistry often gets a bad rep for being that boring subject with math and mixing of liquids. So it’s easy to forget that it literally holds the world together. The objects around us are a product of the way their atoms and molecules interact. Our knives can cut the food on our plates because billions of atoms inside that knife hold onto each other for dear life, and those in food don’t. Diamonds cut through solid stone because carbon atoms can bind to other carbon atoms in structures that are stronger than almost anything else we’ve ever seen. Our cells and tissues are held together by the same interactions. We’re alive because water molecules are shaped in such a way as to make them universal solvents.

We’re still very much working with models here — our understanding of the ties that bind is still imperfect. But even these models can help us appreciate the immense complexity hidden in the most mundane objects around us.

There may be over a million genetic molecules — DNA is just one of them

Credit: Public Domain.

All living things on Earth store information in genetic molecules: either DNA or RNA. But why is it that organisms use only two molecules to store genetic information? What makes DNA and RNA so special? Did the earliest life on Earth actually use a different molecule consisting of different building blocks? These are all important but also very difficult to answer questions — which is where a new study may come in handy.

Researchers at the Tokyo Institute of Technology, the German Aerospace Center (DLR), and Emory University used advanced computational methods to simulate possible nucleic acid-like molecules. They came up with over a million possibilities.

Hereditary molecules

DNA and RNA are known as nucleic acids. These tiny biomolecules not only form the basis for all life on earth, but they’re also key to many treatments for viral diseases such as HIV.

Nucleic acids were first discovered in the 19th-century but it wasn’t until 1953, when Watson and Crick revealed DNA’s double-helical structure, that scientists became aware of their biological and evolutionary functions.

Scientists know about the existence of other nucleic acid-like polymers, but that doesn’t mean that they are capable of storing hereditary information.

“There are two kinds of nucleic acids in biology, and maybe 20 or 30 effective nucleic acid-binding nucleic acid analogues. We wanted to know if there is one more to be found or even a million more. The answer is, there seem to be many more than was expected,” says professor Jim Cleaves of the Earth-Life Science Institute (ELSI) at the Tokyo Institute of Technology

Surprisingly, Cleaves and colleagues found over a million variants of nucleic acid analogs after using sophisticated computational methods that explored the “chemical neighborhood” of DNA and RNA. For instance, although they can have quite different functions, RNA and DNA are separated by the presence of a single atom substitution. There are many more molecules in a similar situation, apparently — with just a minor change, you could end up with a completely new genetic molecule on your hand.

The ultimate aim of this kind of research is to improve our understanding of how the very first life forms appeared on Earth. Most biologists believe that RNA appeared before DNA, however, RNA is also a complex molecule. It is quite possible that a much simple nucleic acid seeded the most primitive life forms. After it served its place and time, this hypothetical genetic molecule was replaced by RNA and then DNA, which became the go-to storage medium for life.

“It is truly exciting to consider the potential for alternate genetic systems based on these analogous nucleosides—that these might possibly have emerged and evolved in different environments, perhaps even on other planets or moons within our solar system. These alternate genetic systems might expand our conception of biology’s ‘central dogma’ into new evolutionary directions, in response and robust to increasingly challenging environments here on Earth,” Dr. Jay Goodwin, a chemist with Emory University and co-author of the new study, said in a statement.

Besides fundamental science, there may also be practical applications for the new investigation, such as new drugs.

Organisms with large genomes, like humans, employ a very complex cellular machinery to copy hereditary information. As such, when copying DNA, these organisms have mechanisms in place that avoid selecting the wrong precursor molecules — otherwise, there might be excessive mutations. Although they’re not technically alive, viruses also have a genome. It is very small, though, and it is far less selective. This fact is exploited by many antiviral drugs, which employ nucleotide analogues that inhibit the virus’ ability to copy its DNA and reproduce.

“Trying to understand the nature of heredity, and how else it might be embodied, is just about the most basic research one can do, but it also has some really important practical applications,” says co-author Chris Butch, formerly of ELSI and now a professor at Nanjing University.

The findings appeared in the Journal of Chemical Information and Modeling.

Coldest chemical reaction reveals intermediate molecules in slow motion

When you chill things close to absolute zero, everything slows down to the point that even the vibration of atoms can come to a grinding halt. This is what researchers at Harvard achieved during an experiment in which they’ve generated the slowest chemical reaction yet. This allowed them to buy enough time to image intermediate chemical compounds that would have otherwise assembled into something else too fast for even our most advanced instruments to follow.

The coldest bonds in the history of molecular chemistry

A diagram showing the transformation of potassium-rubidium molecules (left) into potassium and rubidium molecules (right). Normally the intermediate (middle) step occurs too fast to see but new tech demonstrated by Harvard researchers managed to capture it for the first time. Credit: Ming-Guang Hu.

Absolute zero — the coldest possible temperature — is set at -273.15 °C or -459.67 °F. In experiments closer to room temperature, chemical reactions tend to slow down as the temperature decreases. As you cross into the ultra-cold realm, you’d expect no chemistry at all to happen — but that’s just not true.

Researchers at Harvard University chilled a gas made of potassium and rubidium atoms to just 500 nanoKelvin. For reference, this is millions of times colder than interstellar space.

Even at such frigid temperature, atoms and molecules still react — and they do so slowly enough for scientists to see everything. When the potassium and rubidium molecules interacted, researchers were able to image for the first time the four-atom molecule that was created in an intermediate step.

At room temperature, chemical reactions occur in just a thousandth of a billionth of a second. Previously, scientists used ultrafast lasers like fast-action cameras to snap images of the reactions as they occur. However, because the reaction time is so fast, this method cannot image the many intermediate steps involved in a typical chemical reaction.

“Most of the time,” said Ming-Guang Hu, a post-doc researcher at the department of chemistry and chemical biology at Harvard University and first author of the new study. “you just see that the reactants disappear and the products appear in a time that you can measure. There was no direct measurement of what actually happened in the middle.” 

In the future, scientists will be able to use a similar method to study other chemical reactions in minute detail. Observations aside, such a technique may also enable researchers to tamper with chemical reactions in a more controlled manner, with potential applications in the pharmaceutical, energy, and household product industries.

The findings were reported in the journal Science.

67P/Churyumov-Gerasimenko.

Comet 67P harbors oxygen molecules as old as the Solar System

Molecular oxygen found on the comet 67P/Churyumov-Gerasimenko isn’t produced on the surface — it comes from the early days of the Solar System.

67P/Churyumov-Gerasimenko.

Mosaic of four images taken by Rosetta’s navigation camera (NAVCAM) on 19 September 2014 at 28.6 km (17.8 mi) from the centre of comet 67P/Churyumov–Gerasimenko.
Image credits ESA / Rosetta / NAVCAM.

Between August 2014 and September 2016, the European Space (ESA) Agency’s Rosetta craft tagged along with the comet  67P/Churyumov-Gerasimenko as it was trekking around the Sun. The mission also saw a probe delivered to the comet’s surface.

Among other things, the ESA wanted to use Rosetta to study the comet’s coma — the nebulous envelope around the nucleus of a comet. This structure is created by ice subliming — turning from a solid directly into a gas — on the comet’s surface under the sun’s rays. Rosetta’s analysis of the coma revealed that it contains water, carbon monoxide and dioxide (all compounds we were expecting to find), but also molecular oxygen.

Retro oxygen

Molecular oxygen is composed of two oxygen atoms tied together by a covalent bond. Here on Earth, it’s produced by plants via photosynthesis, but researchers are well aware that oxygen is abundant in many places of the universe — we’ve detected molecular oxygen around some of Jupiter’s moons, for example. By mass, oxygen is the third-most abundant element in the universe, after hydrogen and helium — but finding it around a comet was surprising, to say the least.

With the finding also came questions regarding the origin of this molecular oxygen. Some researchers suggested that it might be produced on the comet’s surface under the action of charged ions in the solar wind.

A new paper published by members of the Rosetta team has analyzed data beamed back by the craft to get to the bottom of the issue. The research, led by researchers from the Imperial College London, found that the proposed ionic mechanism for molecular oxygen generation couldn’t account for levels of this molecule observed in the coma. This would mean that the oxygen molecules Rosetta stumbled upon are primordial — meaning they were already fully formed as the comet itself quickened during the early days of the Solar System 4.6 billion years ago.

“We tested the new theory of surface molecular oxygen production using observations of energetic ions, particles which trigger the surface processes which could lead to the production of molecular oxygen,” said lead author Mr Kevin Heritier. “We found that the amount of energetic ions present could not produce enough molecular oxygen to account for the amount of molecular oxygen observed in the coma.”

The findings don’t rule out oxygen generation at the surface level of 67P — but that the majority of the oxygen in the comet’s coma is simply not produced through such a process.

While there are other theories regarding the origin of 67P’s oxygen, the team didn’t address them in any way, either to confirm or infirm them. So far, however, they say that the primordial oxygen theory is the one which fits available data best. This is further supported by other theoretical work that treats the formation of molecular oxygen in dark clouds and the presence of molecular oxygen in the early Solar System, they add. In the team’s model, preexisting molecular oxygen froze into tiny grains that later clumped together, attracted more material, and eventually got bound up in the comet’s nucleus.

The paper “On the origin of molecular oxygen in cometary comae” has been published in the journal Nature Communications.

A molecular knot with eight crossings. Credit: YouYube/University of Manchester.

Tightest molecular knot could lead to better, stronger materials

Researchers from the University of Manchester, the birthplace of graphene, have made their own molecular Gordian Knot. They used a strand of 192 atoms coiled around a triple loop which crosses itself eight times. It’s the most complex molecular knot ever created and might usher in a new class of super-strong materials.

A molecular knot with eight crossings. Credit: YouYube/University of Manchester.

A molecular knot with eight crossings. Credit: YouYube/University of Manchester.

Knotting and weaving were revolutionary for early humans. This technology brought us clothes, shelter, and new tools which dramatically improved life. David Leigh, a professor of chemistry at the University of Manchester and lead researcher of the new study says molecular knotting could potentially render returns in the same order of magnitude.

“Some polymers, such as spider silk, can be twice as strong as steel so braiding polymer strands may lead to new generations of light, super-strong and flexible materials for fabrication and construction,” Leigh said in a statement.

Molecular braiding

Leigh says tying a knot is similar to weaving, so molecular knots could pave the way for the weaving of molecular strands. Kevlar, the familiar and very tough material used in bullet-proof vests, is actually a plastic whose molecular rods are arrayed in a parallel structure. By interweaving molecular strands we should come up with even tougher, stronger materials. Molecular knots of ever increasing complexity represent baby steps in this direction.

Molecules tie themselves in knots naturally. There are six billion prime knots that we know of which, like prime numbers, can’t be broken down into simpler constituents. As such, you can’t make a new prime knot by stitching other prime knots together.

The first synthesized molecular knot looked like a three-leaf clover. Its configuration, known as a trefoil, was made in 1989 by a team led by eminent chemist Jean-Pierre Sauvage who would go on to win the Nobel Prize for chemistry in 2016 for earlier work that used the same principles. Since then, other small molecules have been arranged in prime knots but the process proved challenging.

In 2012, Leigh’s lab took things an order of magnitude farther after the researchers synthesized a type of molecular knot arranged in a star-shaped structure made up of 160 atoms whose strands crossed five times. Their latest knot has eight crossing points making it even more intricate, as reported in the journal Science.

Not as easy as tying your shoelace

To tie the knot, the molecular building blocks containing carbon, hydrogen, oxygen and nitrogen atoms, along with iron and chloride ions, are all mixed together. The chemical interactions between the atoms and the ions cause them to self-assemble. The metal ions hold the building blocks in the right position while a single chloride ion which sets at the center anchors the whole structure together. Finally, a chemical catalyst links all these building blocks to ‘tie’ the knot.

Right now it’s not clear yet how we can use this knots to make new materials but the potential is there. Leigh and other labs around the world are now faced with the challenge of synthesizing new knots of different configuration until someone makes a structure that proves practically useful.

 

 

Molecules on your mobile phone say a lot about your lifestyle

The mobile phone is often at the core of our modern lifestyle, and that says many things about us in itself. But researchers now believe that they can learn a lot more just by analyzing its screen.

Mirror mirror on the wall, your mobile’s phone screen sees it all. Credit: Amina Bouslimani and Neha Garg

Every time we touch something, we leave behind trace molecules, indicators of the bio-chemistry of our bodies — and there are fewer objects we touch more often than our mobile phones. By analyzing the molecules on phone screens, US scientists were able to reconstruct big chunks of volunteers’ lifestyle, including diet, preferred hygiene products, health status, and locations visited. Even though volunteers were instructed to not use any healthcare products for three days, the traces were still clearly visible.

“All of these chemical traces on our bodies can transfer to objects,” senior author Pieter Dorrestein, PhD, professor in UC San Diego School of Medicine and Skaggs School of Pharmacy and Pharmaceutical Sciences. “So we realized we could probably come up with a profile of a person’s lifestyle based on chemistries we can detect on objects they frequently use.”

Among the identified substances were anti-inflammatory and anti-fungal skin creams, hair loss treatments, anti-depressants, and eye drops – so both internal and external things. There’s good reason to believe that everything you use can be traced back. Food molecules were also detected: citrus, caffeine, herbs and spices were the most prevalent. Meanwhile, insect repellants were detected even though they had been used months before. In other words, the molecules on the phones say quite a lot about the phone’s owner.

“By analyzing the molecules they’ve left behind on their phones, we could tell if a person is likely female, uses high-end cosmetics, dyes her hair, drinks coffee, prefers beer over wine, likes spicy food, is being treated for depression, wears sunscreen and bug spray — and therefore likely spends a lot of time outdoors — all kinds of things,” said first author Amina Bouslimani, PhD, an assistant project scientist in Dorrestein’s lab. “This is the kind of information that could help an investigator narrow down the search for an object’s owner.”

This is an innovative approach which could have an array of potential applications, especially in a legal framework.

“You can imagine a scenario where a crime scene investigator comes across a personal object — like a phone, pen or key — without fingerprints or DNA, or with prints or DNA not found in the database. They would have nothing to go on to determine who that belongs to,” Dorrestein added  “So we thought — what if we take advantage of left-behind skin chemistry to tell us what kind of lifestyle this person has?”

But the team emphasizes that there are other applications as well: medicine, environmental studies, airport screening, or adherence monitoring. For instance, a physician could check if a patient is sticking to the prescription, or exposure to hazardous substances could be studied by analyzing skin metabolites.

Moving forward, they are already working on an even bigger trial, focusing on other objects we often touch during the day, such as wallets and keys.

Journal Reference: Pieter C. Dorrestein et al. Lifestyle chemistries from phones for individual profiling. PNAS, November 2016 DOI: 10.1073/pnas.1610019113

Water

Water squeezed in a new state: not liquid, nor solid or gas. Just pure quantum weirdness

Physicists have crammed water inside extremely small cracks about ten-billionth of a meter and found the molecules entered a never before seen state. In this brand new state, the water molecules don’t adhere to strict laws of classical physics anymore, nor do they behave like a liquid, gas or solid. This weird quantum state has no parallel in our everyday life but nevertheless seems to be a fundamental behaviour of water.

Water

Image: Pixabay

In nature, water infiltrates any nook and cranny. You can find it in soils, but also tiny space like a cell’s walls or within a mineral. Scientists at Oak Ridge National Laboratory investigated what happens to water when it occupies a small space inside a beryl mineral. The beryl channels were only 5 angstroms, where an  angstrom is 10 to the power -10 meters.

Well beyond the nano level, the water molecules behaviour became mainly influenced by quantum physics.

“At low temperatures, this tunneling water exhibits quantum motion through the separating potential walls, which is forbidden in the classical world. This means that the oxygen and hydrogen atoms of the water molecule are ‘delocalized’ and therefore simultaneously present in all six symmetrically equivalent positions in the channel at the same time. It’s one of those phenomena that only occur in quantum mechanics and has no parallel in our everyday experience,” the researchers explain in Physical Review Letters.

A single water molecule is made up an oxygen atom and two hydrogen atoms. The mineral’s channels, which were small enough to allow only one water molecule to sit inside, have a  hexagonal shape due to the crystal structure of beryl. Strikingly, the hydrogen atoms occupied each of the six sides of the channel, with the oxygen atom at the center. Though there were only two hydrogen atoms, these occupied  six different symmetric orientations simultaneously.

Water molecules tunneling a mineral channel. Credit: A. I. Kolesnikov et al.

Water molecules tunneling a mineral channel. Credit: A. I. Kolesnikov et al.

To observe this quantum weirdness, the researchers used neutron scattering — an imaging technique that can expose material properties at the atomic level.

This is the first time such a behaviour has been observed, and physicists aren’t sure how to interpret this newly found knowledge. This happens all the time, though and there are already some potential advantages. For instance, researchers who work with water diffusion through materials that mimic cell walls might find all of this extremely useful.

“This discovery represents a new fundamental understanding of the behaviour of water and the way water utilises energy,” said Oak Ridge researcher Lawrence Anovitz.

 

Big Surprise: Rosetta finds primordial oxygen on a comet

For the first time, astronomers have detected primordial oxygen gassing out from a comet. ESA’s Rosetta shuttle made the surprising  in situ discovery on the comet 67P/Churyumov–Gerasimenko. The fact that they found pure oxygen molecules (O2) indicates that the oxygen came from the initial comet formation.

Rosetta’s detection of molecular oxygen. Image via ESA.

Oxygen is the third most abundant element in the Universe, but its simplest molecular form (O2) is surprisingly hard to find and pinpoint. Even in star forming clouds, oxygen is highly reactive so you generally see it bound to other elements, which is why it was quite surprising to find it on a comet.

“We weren’t really expecting to detect O2 at the comet – and in such high abundance – because it is so chemically reactive, so it was quite a surprise,” says Kathrin Altwegg of the University of Bern, and principal investigator of the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis instrument, ROSINA.

Rosetta’s detection of molecular oxygen

Rosetta has been studying 67P/Churyumov–Gerasimenko for over a year and has detected an abundance of different gases pouring from its nucleus. Water vapour, carbon monoxide and carbon dioxide are found in abundance, with nitrogen, sulphur and even noble gases also reported. We know this first hand, as Rosetta’s Philae lander successfully made the first soft landing on a comet nucleus when it touched down on Comet Churyumov–Gerasimenko on 12 November 2014.

“It’s also unanticipated because there aren’t very many examples of the detection of interstellar O2. And thus, even though it must have been incorporated into the comet during its formation, this is not so easily explained by current Solar System formation models.”

Overall, the team analyzed 3000 samples collected around the comet in the past year and found an abundance of 1–10% relative to H2O, with an average value of 3.80 ± 0.85% – 10 times more than astronomers were expecting. No ozone was detected.

Ref: Abundant molecular oxygen in the coma of 67P/Churyumov–Gerasimenko,” by A. Bieler et al is published in the 29 October 2015 issue of the journal Nature.

In this artist's illustration, the NaK molecule is represented with frozen spheres of ice merged together: the smaller sphere on the left represents a sodium atom, and the larger sphere on the right is a potassium atom. Illustration: Jose-Luis Olivares/MIT

Scientists cool molecules just a hair over absolute zero (1,000,000 times colder than space)

In a breakthrough moment, researchers at MIT successfully cooled sodium potassium gas molecules (NaK) near absolute zero. At this temperature, matter behaves significantly different and starts exhibiting quantum effects. This is the coldest any molecule has been measured so far.

In this artist's illustration, the NaK molecule is represented with frozen spheres of ice merged together: the smaller sphere on the left represents a sodium atom, and the larger sphere on the right is a potassium atom.  Illustration: Jose-Luis Olivares/MIT

In this artist’s illustration, the NaK molecule is represented with frozen spheres of ice merged together: the smaller sphere on the left represents a sodium atom, and the larger sphere on the right is a potassium atom.
Illustration: Jose-Luis Olivares/MIT

Normally, at ambient temperature, molecules zip by at colossal speeds, colliding and reacting with each other. There probably are millions of such collisions happening every moment in the air you breath. When matter gets really cold though, its movements near to a halt as it’s chilled closer and closer to absolute zero (0 Kelvin or -273.15 degrees Celsius). Other strange things start happening as well. For instance, when Helium is cooled down to near zero the substance (a gas at room temperature) turns into a liquid with no viscosity – a superfluid. But it’s a lot easier to cool single atoms, like He, than molecules, which comprise two or more atoms linked by electromagnetic forces.

Molecules are a lot more complicated since they exhibit more complex degrees of freedom:  translation, vibration, and rotation. So, cooling the molecules directly is challenging, if not impossible with current means. To cool the sodium potassium gas, the researchers had to employ multiple steps. First, the MIT team used lasers and evaporative cooling to cool clouds of individual sodium and potassium atoms to near absolute zero. Typically, sodium and potassium don’t form compounds because they repel each other. However, the researchers “glued” them together by prompting the atoms to bond with an electromagnetic field. This mechanism is known as “Feshbach resonance.”

The resulting bond, however, is very weak – a “fluffy molecule”, as the researchers call it. To bring the atoms closer together, and strengthen the bond as a consequence, the researchers employed a novel technique used previously  in 2008 by groups from the University of Colorado, for potassium rubidium (KRb) molecules, and the University of Innsbruck, for non-polar cesium­ (Ce) molecules. Yet again, the weak molecules were exposed to a pair of laser pulses, the large frequency difference of which exactly matched the energy difference between the molecule’s initial, highly vibrating state, and its lowest possible vibrational state. The sodium potassium molecule absorbed the lower energy from one laser and emitted energy to the higher-frequency laser. So, what the MIT researchers got at the end were very low energy state, ultra-cold molecules sitting as low as 500 nanoKelvins or just billionths of a degree above absolute zero.

The resulting ultra-cool molecules were quite stable, with a relatively long lifetime, lasting about 2.5 seconds. The molecules also exhibited very strong dipole moments — strong imbalances in electric charge within molecules that mediate magnet-like forces between molecules over large distances. Concerning their speed, at such a cool temperature, the molecules average speeds of centimeters per second and are almost at their absolute lowest vibrational and rotational states.

“In the case where molecules are chemically reactive, one simply doesn’t have time to study them in bulk samples: They decay away before they can be cooled further to observe interesting states,” says Martin Zwierlein, professor of physics at MIT and a principal investigator in MIT’s Research Laboratory of Electronics. “In our case, we hope our lifetime is long enough to see these novel states of matter.”

The next step is cooling the molecule even further to maybe catch a glimpse of the quantum mechanical effects that are predicted should happen.  Findings appeared in the journal Physical Review Letters.

“We are very close to the temperature at which quantum mechanics plays a big role in the motion of molecules,” Zwierlein says. “So these molecules would no longer run around like billiard balls, but move as quantum mechanical matter waves. And with ultracold molecules, you can get a huge variety of different states of matter, like superfluid crystals, which are crystalline, yet feel no friction, which is totally bizarre. This has not been observed so far, but predicted. We might not be far from seeing these effects, so we’re all excited.”

edit: missed a very important “minus” sign for the absolute zero temperature value in Celsius (-273.15 degrees Celsius)

In square ice (left) water molecules are locked at a right angle. This looks nothing like the familiar hexagonal ice (right).

Sandwiching water between graphene makes square ice crystals at room temperature

In a most unexpected find, the same  University of Manchester team that isolated graphene for the first time in 2003 found that water flattens into square crystals – a never encountered lattice configuration – when squeezed between two layers of graphene. The square ice qualifies as a new crystalline phase of ice, joining 17 others previously discovered. The finding could potentially improve  filtration, distillation and desalination processes.

Water, don’t be square

In square ice (left) water molecules are locked at a right angle. This looks nothing like the familiar hexagonal ice (right).

In square ice (left) water molecules are locked at a right angle. This looks nothing like the familiar hexagonal ice (right).

Previously, Andre Geim of the University of Manchester, UK – who shared a Nobel Prize in physics in 2010 for his groundbreaking graphene research – was left scratching his head after he found water vapours could pass through laminated sheets of graphene oxide. This was peculiar since helium couldn’t do this, a molecule that’s a lot smaller than water. To complicate the puzzle, liquid water – which is more tightly bonded than vapor – could also pass through the graphene oxide.

Then, simulations showed that water was forming square ice crystals between the graphene sheets. “But you never trust molecular-dynamics simulations,” says Geim. The team thus proceeded with a simple experiment. They dropped just one milliliter of water on a sheet of graphene (an one atom thick layer carbon arranged in a hexagon lattice), then placed a second one on top. As the water slowly evaporated, it was reduced to an one atom thick layer (just like the graphene!), all arranged in a square lattice at room temperature.

This electron scan microscope image clearly shows how the square ice looks like. Image: NATURE

This electron scan microscope image clearly shows how the square ice looks like. Image: NATURE

In normal conditions (temperature and pressure), the water molecule has a V shape, with the two hydrogen atoms bonded to the oxygen atom at a 105° angle. Imagine Mickey Mouse, that’s water! In ice form,  four bonds are usually arranged in a tetrahedral (pyramid) shape. In the square ice, however, all the atoms line up with a right angle between each oxygen–hydrogen bond.

After several iterations of the experiment, Geim’s team ended up with one, two or three atom thick layers of square ice crystals, all aligned one atop another. Remember, I mentioned the water molecules were squeezed by the graphene. In fact, the pressure exerted by the two layers could be more than 10,000 times that of  atmospheric pressure, according to the paper published in Nature. This happens because as the graphene sheets get closer, they distort each others’ electron cloud. The sheets are attracted to one another by a huge intermolecular force known as the van der Waals force, like “having millions of little springs holding them together,” according to Alan Soper, a physicist at the Rutherford Appleton Laboratory in Harwell, UK.

This might not be some queer finding confined to a laboratory setting. Square ice might be encountered in nature where enormous pressure is exerted over tight quarters. It just may be that we haven’t found it yet. On a practical level, the square ice method might  improve desalination filters based on graphene.

“Finding out how the water behaves in a capillary is a big part of what we need to do to make a good filter,” says Geim. “This is a very important step.”

 

octopus tentacle

Why octupus arms never get entangled

octopus tentacle

Photo: c4dcafe.com

Roboticists and mechanical engineers hold octopuses to great respect and admiration because of their many skills, like great water propulsion, camouflage and independent limbs. Each octopus tentacle is equipped with numerous suckers that allows it to easily cling to most surfaces, no matter how smooth they may be. Whether the octopus needs to attach itself to a surface or run away quickly, its arms are always there to help, but what’s startling about all this is that the arms have a mind of their own: the brain doesn’t know where its arms are since there aren’t any nerve endings that communicate this information. With all this in mind, how in the world does an octopus manage not to get its arms stuck together in the first place?

These ‘shoelaces’ never tie together

Guy Levy, a neuroscientist at the Hebrew University of Jerusalem, along with colleagues decided to investigate this intriguing phenomenon and devised a series of experiments to find the answer. Mostly, the researchers threw amputated octopus arms (an amputated octopus limb is still lively an hour after it was cut from the body) in batches around water basins. When two amputated arms came close to each other, the arms were unable to grasp each other despite being separated from the body.

The researchers initially thought the octopus arms manage to avoid each other through an electrical mechanism, however the amputated arm immediately clanged to some other skinned  amputated arm. This means that there’s something in or on the octopus skin that prevents its arms from coming together.

In another experiment, the researchers proved that the mechanism wasn’t texture either, after amputated arms couldn’t grab “reconstructed skin” that had been broken down to its constituent molecules and embedded in a gel. The only possible explanation that remains is a chemical mechanism.

“Everybody knew the lack of knowledge in octopus arms, but nobody wanted to investigate this,” says Guy Levy, a neuroscientist at the Hebrew University of Jerusalem and a co-author of the study. “Now we know that they have a built-in mechanism that prevents them from grabbing octopus skin.”

Sticky fingers

This chemical mechanism is a lot more subtle that anyone might have thought. For instance, the octopus has an off-switch that blocks the molecule  that normally causes the octopus arms to repel any other surface lined with octopus skin. This is how the animals manage to ‘hug’ and grasp one another. Otherwise, there couldn’t have been any mating. Still, there is much the researchers don’t know.

“We do not know which molecules are involved,” Levy says, “but we do know that molecules in the skin are sensed in the suckers and this inhibits the attachment behavior.”

Future efforts will concentrate on identifying the molecule or group of molecules that cause the arms’ suckers to avert octopus skin, as well assessing whether other  species of octopuses and cephalopods use the same mechanism. If they can find out how the octopus does this, Levy and robotician colleagues might be able to create some very interesting devices and robots. For instance, Levy is already working with a soft-robotics group called  STIFF-FLOP with whom he wants to create special surgical tools that preferentially and automatically avoid grasping certain objects.

“We are aiming at building a surgical soft-manipulator that might be able to scroll inside the human body while avoiding interactions between arms and parts of the human environment that aren’t involved in its tasks — like intestinal walls.”

The work appeared in the journal Current Biology.

N. Farsad et al./PLOS ONE

Sending a text message using Vodka molecules – the first continuous molecular communication

In nature, organisms communicate in various ways, be it through acoustic or biological signals. Insects, for instance, communicate and relay important information, such as a threat to a hive, using pheromones – an excreted chemical with a particular signature. Scientists at the University of Warwick in the UK and the York University in Canada have created a molecular communications system which they used to send a continuous signal, like a text message, just by spraying alcohol molecules. The system in a more advanced form could facilitate communication in environments where electromagnetic waves can’t be used, like through pipelines or oil rigs.

N. Farsad et al./PLOS ONE

N. Farsad et al./PLOS ONE

Previous attempts also relayed information using molecular signaling, however this is the first time continuous data transmission has been achieved. Moreover, the system was built using off-the shelf components with an overall cost that doesn’t exceed $100.

Molecular receiver: one of three sensors (for various types of tests) demodulates the incoming signal by assigning the bit 1 to increasing concentration and 0 to decreasing. The binary data is converted back to letters in the Arduino board and sent via serial port to a computer for display. (Credit: N. Farsad et al./PLOS ONE)

Molecular receiver: one of three sensors (for various types of tests) demodulates the incoming signal by assigning the bit 1 to increasing concentration and 0 to decreasing. The binary data is converted back to letters in the Arduino board and sent via serial port to a computer for display. (Credit: N. Farsad et al./PLOS ONE)

The message is inputted through an LCD Shield Kit then encoded by an Arduino board as a binary sequence – 1 corresponds to higher concentration of molecules, while 0 to lower concentration. In their demonstration, the researchers programmed a sprayer to release evaporated alcohol molecules several meters across open space before it was decoded by a receiver. The message was “O Canada” – a tribute to the Canadian national anthem.

A sprayed text message

“We believe we have sent the world’s first text message to be transmitted entirely with molecular communication, controlling concentration levels of the alcohol molecules, to encode the alphabets with single spray representing bit 1 and no spray representing the bit 0,” said York doctoral candidate Nariman Farsad, who led the experiment.

“Imagine sending a detailed message using perfume — it sounds like something from a spy thriller novel, but in reality it is an incredibly simple way to communicate,” said Dr. Weisi Guo from the School of Engineering at the University of Warwick.

“Of course, signaling or cues are something we see all the time in the natural world — bees for example use chemicals in pheromones to signal to others when there is a threat to the hive, and people have achieved short-range signaling using chemicals.

“But we have gone to the next level and successfully communicated continuous and generic messages over several meters.

The system could find potential use in medicine. Recent advancements have allowed nanoscale devices to be embedded into organs, for instance, where they sense and gather important data. In this tiny environment, however, there are some constraints to using electromagnetic waves to propagate information – after all an antenna can only be so small. Chemical communication require very little energy, is bio-compatible and could thus provide the means to solve this problem.

A more immediate practical application, however, may be seen in places like pipe lines, sewers or oil rigs. The molecular communication system could be used here to send important safety information and advert potentially catastrophic accidents.

The system was described in a paper published in the journal PLOS ONE.

Harvard and MIT scientists create photon molecules

Photons and molecules

Mikhail Lukin - image via Harvard.

Mikhail Lukin – image via Harvard.

Scientists managed to ‘trick’ photons (the elementary particles of light and all other forms of electromagnetic radiation) into forming molecules for the first time – a state of matter that until recently had been purely theoretical.

Scientists from Harvard University and the Massachusetts Institute of Technology (MIT) are challenging the current paradigm – they want physicists to rethink what they know about light, and they didn’t have to go in another galaxy to do this.

What happened is that a group led by Harvard Professor of Physics Mikhail Lukin and MIT Professor of Physics Vladan Vuletic managed to coax photons into binding together to form molecules. The discovery goes against decades of accepted theories and ideas on light. Photons have constantly been described as massless particles that don’t interact with each other (they are only considered to have a mass when they are moving). Shine two photon lasers at each other, and the rays will simply pass through each other – photonic molecules seems a nonsensical term.“Most of the properties of light we know about originate from the fact that photons are massless, and that they do not interact with each other,” Lukin said. “What we have done is create a special type of medium in which photons interact with each other so strongly that they begin to act as though they have mass, and they bind together to form molecules. This type of photonic bound state has been discussed theoretically for quite a while, but until now it hadn’t been observed.

What they did isn’t really a photon laser, but rather a… light saber.

Using the Force

"Photonic molecules" behave less like traditional lasers and more like something you might find in science fiction -- the light saber. (Credit: © Yana / Fotolia)

“Photonic molecules” behave less like traditional lasers and more like something you might find in science fiction — the light saber. (Credit: © Yana / Fotolia)

“It’s not an inapt analogy to compare this to light sabers,” Lukin said. “When these photons interact with each other, they’re pushing against and deflecting each other. The physics of what’s happening in these molecules is similar to what we see in the movies.”

But Harvard researchers can’t really rely on “The Force”, so instead, they began by pumping rubidium atoms into a vacuum chamber. After a while, they used lasers to cool the cloud of atoms to just a few degrees above absolute zero (the lowest thermodynamic temperature – −273.15° on the Celsius scale, −459.67° on the Fahrenheit scale). Then, using very weak lasers, they fired single photons into the cloud of atoms. As the photons enter the cloud, they give energy to atoms along their path, which causes them to slow dramatically. As the photons move through the cloud, that energy is handed off from atom to atom, and eventually exits the cloud with the photon.

“When the photon exits the medium, its identity is preserved,” Lukin said. “It’s the same effect we see with refraction of light in a water glass. The light enters the water, it hands off part of its energy to the medium, and inside it exists as light and matter coupled together. But when it exits, it’s still light. The process that takes place is the same. It’s just a bit more extreme. The light is slowed considerably, and a lot more energy is given away than during refraction.”

But when Lukin and his colleagues fired two photons into the cloud, they were really surprised to see the results – the two photons came out of the cloud together, as a single molecule. This is the effect of a rather strange and unintuitive effect, called the Rydberg blockade, which means that when an atom is excited, nearby atoms cannot be excited to the same degree. What this means for this case in particular, is that as the first photon excites an atom, it must move forward before the second one can excited nearby atoms. What’s interesting is that they tend to retain this molecule-like behavior even after exiting the cloud.

 

Photons with strong mutual attraction in a quantum nonlinear medium. Credit: Nature.
Photons with strong mutual attraction in a quantum nonlinear medium. Credit: Nature.

 This could prove to be valuable for developing quantum computers; quantum logic requires interactions between individual quanta so that quantum systems can be switched to perform information processing.

“What we demonstrate with this process allows us to do that,” Lukin said. “Before we make a useful, practical quantum switch or photonic logic gate, we have to improve the performance. So it’s still at the proof-of-concept level, but this is an important step. The physical principles we’ve established here are important.”

The process could be used in the future to create 3D structures, such as crystals, solely out of light.

“What it will be useful for we don’t know yet. But it’s a new state of matter, so we are hopeful that new applications may emerge as we continue to investigate these photonic molecules’ properties,” he said.

The paper detailing the "intelligent molecule" research has been chose as the cover article for ACS Nano, in combination with a 3D graphic of the NIM-media designer. (c) ACS Nano

Intelligent molecules that fold and change shape demonstrated for the first time

The new results demonstrate at the single-molecule level how solvent-induced collapse of an environmentally responsive copolymer modulates surface adhesion forces and bridging length distributions in a controllable way. (c) (Credit: Michael A. Nash, and Hermann E. Gaub/ACS Nano)

The new results demonstrate at the single-molecule level how solvent-induced collapse of an environmentally responsive copolymer modulates surface adhesion forces and bridging length distributions in a controllable way. (c) (Credit: Michael A. Nash, and Hermann E. Gaub/ACS Nano)

In an amazing breakthrough, scientists at Ludwig-Maximilians-Universität (LMU) have for the first time demonstrated an extremely appealing, yet still obscure concept – intelligent molecules. By definition intelligence is the ability to learn and understand or deal with new situation and the latter is exactly what the researchers’ polymer molecules can do, namely  react to external stimuli and reversibly change their shape.

The applications for such a smart molecule could be numerous. For instance, as nanoswitches: hot-cold, light-dark, altered salt concentrations or some other stimuli factors could be toggled or switched, in the process becoming stimulus generator by itself. Also, these could also be used in biosensors, drugs, chromatography procedures, and other applications, the researchers suggest.

The paper detailing the "intelligent molecule" research has been chose as the cover article for ACS Nano, in combination with a 3D graphic of the NIM-media designer. (c) ACS Nano

The paper detailing the “intelligent molecule” research has been chose as the cover article for ACS Nano, in combination with a 3D graphic of the NIM-media designer. (c) ACS Nano

The physicists demonstrated the concept by successfully making a reaction with a single polymer molecule visible for the first time. The researchers engineered a synthesized polymer which they then placed on a gold surface, very carefully, with an atomic force microscope (AFM). One of the ends of the polymer adhered to the surface, while the other to the tip of the AFM. Once the scientists increased the salt concentration of the surrounding medium, they were able to observe how the molecule collapsed gradually. Back in a weak salt solution, the molecule unfolds again

“We have observed both processes in our study for the first time for a single polymer molecule,” write the researchers.

The findings were reported in the journal ACS Nano.

source: press release

single molecule electric charge imaging

IBM images electric charge distribution in a SINGLE molecule – world’s first!

Part of a the recent slew of revolutionary technological and scientific novelties coming off IBM‘s research and development lab, the company has just announced that it has successfully managed to  measure and image for the first time how charge is distributed within a single molecule. The achievement was made possible after a new technique, called Kelvin probe force microscopy (KPFM), was developed. Scientists involved in the project claim that the research introduces the possibility of imaging the charge distribution within functional molecular structures, which hold great promise for future applications such as solar photoconversion, energy storage, or molecular scale computing devices. Until now it has not been possible to image the charge distribution within a single molecule.

single molecule electric charge imaging The team, comprised of scientists Fabian Mohn, Leo Gross, Nikolaj Moll and Gerhard Meyer of IBM Research, Zurich, imaged the charge distribution within a single naphthalocyanine molecule using what’s called Kelvin probe force microscopy at low temperatures and in ultrahigh vacuum – these conditions were imperative, as a high degree of thermal and mechanical stability and atomic precision of the instrument was required over the course of the experiment, which lasted several days.

Derived off the revolutionary atomic force microscopy (AFM), the KPFM measures the potential difference between the scanning probe tip and a conductive sample, in our case the naphthalocyanine molecule – a cross-shaped symmetric organic molecule. Therefore, KPFM does not measure the electric charge in the molecule directly, but rather the electric field generated by this charge.

“This work demonstrates an important new capability of being able to directly measure how charge arranges itself within an individual molecule,” says Michael Crommie, professor for condensed matter physics at the University of Berkeley.

“Understanding this kind of charge distribution is critical for understanding how molecules work in different environments. I expect this technique to have an especially important future impact on the many areas where physics, chemistry, and biology intersect.”

The potential field is stronger above areas of the molecule that are charged, leading to a greater KPFM signal. Furthermore, oppositely charged areas yield a different contrast because the direction of the electric field is reversed. This leads to the light and dark areas in the micrograph (or red and blue areas in colored ones).

The new KPFM technique promises to offer complementary information about a studied molecule, providing valuable electric charge data, in addition to those rendered by scanning tunneling microscopy (STM) or atomic force microscopy (AFM). Since their introduction in 1980′, STM, which images electron orbitals of a molecule, and ATM, which resolves molecular structure, have become instrumental to any atomic and molecular scale research today, practically opening the door to the nanotech age. Maybe not that surprisingly, the STM was developed in the same IBM research center in Zurich, 30 years ago.

“The present work marks an important step in our long term effort on controlling and exploring molecular systems at the atomic scale with scanning probe microscopy,” Gerhard Meyer, a senior IBM scientist who leads the STM and AFM research activities at IBM Research – Zurich.

The findings were published in the journal Nature Nanotechnology. 

Source / image via IBM

5th grader discovers new molecule, gets co-author status

Kenneth Boehr was doing the usual chemistry class, not expecting more than you would from any other ten year old students. The same for Clara Lazen, one of his students, who started working on a molecule building kit, while looking at the periodic table she was handed; she handed her teacher a model constructed from oxygen, nitrogen, and carbon atoms, and asked if she’d made a real chemical or not – and the teacher was stumped. It was unlike any other molecule he had ever seen before, but it looked correct from every point of view. So he took a picture and sent it to an old college buddy of his, Robert Zoellner, professor of chemistry at Humbolt State University.

The results were quite amazing, for everybody. As it turns out, Clara Lazen put together an entirely new, viable molecule, which on top of all, can actually be synthesized in a lab, showing some pretty practical applications too. Tetrakis(nitratoxycarbon) methane, or tetranitratoxycarbon, as the molecule can be named (though the 10 year old would probably have a harder time spelling it than creating its model) has the potential to store energy, or be used as an explosive.

The only problem is, it has to be created first – something which Zoellner couldn’t do by himself. So he published a paper about its structure in Computational and Theoretical Chemistry, giving Clara co-author status, and inviting other researchers to create the molecule. What does she have to say about all this? Well, she has found a renewed interest for biology and medicine, and is thrilled she was given the chance to do something useful.

Source

Researchers find marijuana spreads and prolongs pain

We’ve all endured some kind of physical pain, more or less intense. When you hit your finger while hammering, for example, the pain is really intense, but passes away (at least mostly) in just a few moments. So scientists were trying to find out why is it that some intense pains pass so quickly and why some have to be endured for more time.

Researchers from the University of Texas Medical Branch of Galveston believe they have, at least partially, found the answer, which is, believe it or not, in a group of compounds that include cannabinoids, the active ingredients in marijuana, or weed, as anybody under 40 (and not only) knows it as. This proves to be very interesting, given the recent research and interest in medical use of marijuana for pain relief. According to this study, the results are the exact opposite, as endocannabinoids, which are produced by human body (and not only) prolong pain istead of damping it down.

“In the spinal cord there’s a balance of systems that control what information, including information about pain, is transmitted to the brain,” said UTMB professor Volker Neugebauer, one of the authors of the Science article, along with UTMB senior research scientist Guangchen Ji and collaborators from Switzerland, Hungary, Japan, Germany, France and Venezuela. “Excitatory systems act like a car’s accelerator, and inhibitory ones act like the brakes. What we found is that in the spinal cord endocannabinoids can disable the brakes.”

In order to get to this conclusion they applied a ‘biochemical mimic’ to the inhibitory neurons on slices they took from mouse spinal cord. Electrical signals that should have produced an inhibitory response were ignored. They then proceeded to analyze spinal cord slices taken from genetically engineered mice that lacked receptors for the endocannabinoid molecules and they found that the so called ‘brakes’ work.

“To sum up, we’ve discovered a novel mechanism that can transform transient normal pain into persistent chronic pain,” Neugebauer said. “Persistent pain is notoriously difficult to treat, and this study offers insight into new mechanisms and possibly a new target in the spinal cord.”

Meet the magnetic superatoms

dadaVirginia Commonwealth University managed to discover what they have called a ‘magnetic superatom‘, a stable cluster of atoms that can ‘impersonate’ various elements from the periodic table, that could be put to use in numerous fields, especially for biomedical purposes and to create molecular devices for the next generation of computer memory.A team from the

This cluster consists of one atom of vanadium and eight cesium. Together, they act like a tiny magnet that mimics a single manganese atom in magnetic strength but allows electrons with certain spin orientations to flow through the surrounding shell atoms.

The team was led by Shiv N. Khanna, Ph.D., professor in the VCU Department of Physics, together with VCU postdoctoral associates J. Ulises Reveles, A.C. Reber, and graduate student P. Clayborne, and collaborators at the Naval Research Laboratory in D.C., and the Harish-Chandra Research Institute in Allahabad, India; they teamed up together to go against what can only be called a titanic quest, namely examining the magnetic and electronic properties of the clusters.

They found out that the eight cesium atoms provide extra stability due to a filled electronic state. Also, when one atom combines with others, it tends to lose or gain valence until it reaches stable configuration. As Khanna points out:

“An important objective of the discovery was to find what combination of atoms will lead to a species that is stable as we put multiple units together. The combination of magnetic and conducting attributes was also desirable. Cesium is a good conductor of electricity and hence the superatom combines the benefit of magnetic character along with ease of conduction through its outer skin,” Khanna said. A combination such as the one we have created here can lead to significant developments in the area of “molecular electronics,” a field where researchers study electric currents through small molecules. These molecular devices are expected to help make non-volatile data storage, denser integrated devices, higher data processing and other benefits,” he said.