On Z(4430) the Tetraquark


Scientists are always finding new particles or new phenomena that enlarge our existing pool of knowledge. And said pool has just become larger thanks, once again, to the LHC, which now says they have found a new type of matter.

Matter can be found in many forms, from solids in a macroscopic level, to protons, and even further down, to quarks. These last ones are the most primary building blocks in our universe. They make up protons and neutrons, which then form atoms, which then form elements and then everything we see nowadays.
But quarks don’t exist just by themselves. The come together in groups of two, called mesons, or in groups of three, which form protons and neutrons. But now, the LHC has supposedly found a new particle that consists of 4 quarks, forming a tetraquark. This mythical particle is being called Z(4430), due to the current naming system which says all ‘tetraquarks’ need to have names starting with a Z, for organisational purposes.

Z(4430)

Graph of results proving the existence of Z(4430)

Up until now, they had only been theorised, never actually proved, since the necessary calculations were far too complicated for even our most modern computers to attempt. But even then, this is not the first time a tetraquark has been presumably found. It has happened only once before, in the Belle Detector in Japan, where they also thought they had detected a tetraquark. In that case, other labs tried to find the particle, but since they were unable to do so, the particle’s existence was severely questioned.
The difference this time is that the LHC has detected Z(4430) for over 4000 times, in over 10 times the amount of data the Belle Detector had, undoubtedly proving this particle something worth studying.

There is, however, a slight problem with this particle. The basic theoretical models, (those that can be carried out without the use of complex computers), predict that tetraquarks should have a decay time of 10 times the decay time of Z(4430). This nagging little obstacle will have to be passed with more research into this particle, to finally unravel the mystery of whether this particle is just another mistake in the history of science, or if it is in fact one of the basic fragments of nature.

Embracing New Organs


There is a wide variety of diseases, such as cystic fibrosis, kidney failure… that can be treated or even cured with an organ transplant. However, a disadvantage of this otherwise great cure is the fact that since the new organ doesn’t really come from you, your immune system might attack it. The current solution to this problem is a mixture of immunosuppressant drugs, which although work in making the body accept foreign organs, they can cause very uncomfortable and serious side effects.

This problem is what lead Allan Kirk, scientist at Emory University in Atlanta, Georgia, to look for possible alternatives. His team and himself eventually managed to create a small group of drugs, only three, to substitute the previous cocktails of medicines. What’s even better is that his drugs can even reset the immune system so that the patient must only take one drug every month instead of daily, as they do now.

Well then let’s meet his three drugs and learn how they work. The first one is alemtuzumab, and has to be given at the same time the organ transplant is happening. What it does is it completely destroys all white blood cells in the patient’s body that might attack the organ. It’s like making the immune system and its army of defenders start from 0.
The following drug is belatacept, and is given to the patient when new white blood cells start to appear. This drug acts in a way that makes the new cells accept the new organ as part of the patient and leave it in peace.
Lastly, a dose of sirolimus is administered. It is a normal, immunosuppressant drug whose function is to prevent any of the white blood cells that survived the original massacre from the alemtuzumab from damaging the organ.
Altogether, most patients would only have to take the initial drugs, and after those, only one injection a month, which is considerably more comfortable than the current treatment.

pills

This cocktail of drugs has been replaced by only 3 drugs

Kirk has been carrying his experiments in a group of 13 people, and a year after they started the treatment none of them have shown signs of rejection. But Kirk has had to ask them if they wanted to stop taking the sirolimus and most did. The ones who chose to keep with it are perfectly fine, and those who got off of it are also fine, but now have to take monthly belatacept injections.

The implications of this revolutionary treatment are incredible. Up until now it has only been tested on a small sample of people, and all with kidney transplants, but Kirk and his team plan on doing larger groups with other organ transplants.

Robot Yeast


A milestone in biology was reached this month when scientists in USA were able to create an entirely synthetic chromosome from a Saccharomyces cerevisiae, commonly known as yeast, in the lab.

chromosome

A chromosome has been created for the first time in the lab, step by step

To start this process they identified the full genetic sequence of yeast’s chromosome III, chosen because it’s one of the smallest chromosomes and can therefore be replicated more easily.
But it was still too big, so they took out a few less than 45,000 nucleotides, all of those thought to be ‘junk’ DNA, that is, DNA that doesn’t seem to have any function. This left 270,000, all of which had to be joined together to make up the chromosome, starting from scratch.
This is an enormous amount of work, so they ended up working with a team of 60 undergraduates, each team building a part of the chromosome until they were all joined together to form the final masterpiece.
Once the chromosome was ready, they inserted it into the yeast cell, and fortunately it seemed to work just as fine as the natural one would. They are now working on repeating this task on the whole of the yeast’s genome, instead of only one chromosome.

There have been some experiments in the past which managed to recreate the genome of organisms, especially bacteria, but no one up until now had managed to change it so much and still have it work. It is an outstanding feat in science that could teach biologists a lot more on how genes work and interact with each other.

However, this achievement is not only good in the way of creating artificial life, but it could also show some improvements in the chemical industry world.
When they decided which nucleotides to take out, they also haad to chose some changes to be made to the genome, so as to learn something from the genes changed. One of these tweaks was to change the stop codon, TAG, to TAA. This meant that TAG now doesn’t code for anything, but scientists could change this so it codes for a new amino acid, not found in the cell before. This could give rise to new substances and biopolymers, whose properties could prove to be very useful. If this worked, we could eventually have cells become factories, all with changed genetic sequences, so they produced new chemicals for many possible functions.

Humans Are Suprisingly Nosy


There have been plenty of studies on the human vision and hearing senses, but there is rarely one on our smelling sense. But this time, a group of researchers at Rockefeller University in NYC decided to break the rule and have arrived to a fascinating conclusion.

rose

A rose’s smell is composed of many odorant molecules that combine to give off that particular scent

Normally, a smell is a mixture of hundreds of different odorant molecules, and particular combinations of these give rise to a variety of smells, such as chocolate and flowers.
Based on this idea, these scientists produced three types of mixtures out of 128 odours, having 10, 20 or 30 of them in each mixture with different combinations. These were then given to a group of inexperienced volunteers, in the form of three samples: two of the same mixture and a different one.

Results were collected, and using mathematics such as the probability theory, they reached the verdict that there were more than a trillion combinations of those odours, which is also quite an underestimate since there are many more existing odours.
These results differ drastically from previous experiments, like the last one, made in the 1927, which said that humans were able to tell only 10,000 smells apart.
Not only that, but it also makes the olfactory sense defeat the visual sense since it can distinguish far more stimuli. In fact, the human eye can differentiate 10 million colours (which is still pretty good), but means that our sense of smell is 100,000 times more varied than the sense of vision.

The obvious conclusion was that the more common odorants two substances shared, the harder it was to distinguish them. However, volunteers proved to be quite good at distinguishing smells, but not as good at naming them. A possible reason is that although we have more than 400 receptors in our nose, the olfactory nerves are not connected to the area in the brain where language is used.
It is still very remarkable that humans have the capability of setting apart such a great number of smells, and scientists are already working on expanding their knowledge on the smelling sense using this investigation and its consequences.

Detecting Baby Waves


In Einstein’s theory of general relativity, he said that massive objects moving at incredible speeds, or giant objects’ gravity interacting could cause ripples in the space-time fabric, known as gravitational waves. They had been searched by scientists for years, and they had successfully hidden, but not anymore.

A series of experiments taking place in the South Pole have finally provided the scientific community with a solid detection of these elusive waves. The project, called BICEP2, has released its findings today, and are awaiting further revision for official publication.

gravitational echo

The graph showing the primoridal gravitational waves when first detected.

There has been a lot of excitement over these waves, because they are able to prove one of the most popular theories regarding the birth of our universe: inflation. The theory, suggested by physicist Alan Guth, says that a few moments after the universe was created, it suffered a dramatic increase in size (by a factor of 1078). After this, its expansion rate slowed down considerably.

What’s important is that if this theory was correct, the sudden growth would have caused ripples in the space-time, hopefully strong enough for us to detect.

And this is what this amazing team has done. They have detected the gravitational waves that were given off during the expansion, given the fancy name of primordial gravitational waves.

The results are impressive just by themselves. The fact they have caught these waves is already world-changing, but there are even more interesting details that deserve our attention.

The waves they found were stronger than they thought they could be, which leads to a rethinking of the current inflation theory. There are some ‘sub-theories’ that can explain this fact, so many eyes are turning towards these and reconsidering them for answers.

But if there’s something we’ve learnt after all these years is to remain cautious after big discoveries (incredible stem cell method not that incredible after all?). The findings have yet to be backed up by other experiments from other teams, but overall there is a positive feeling towards this data.

If they were to be true, they would prove inflation to be true once and for all, but they could also prove useful in completing quantum mechanics. This field is very effective when working with subatomic particles, but when you add gravity, it all goes to rubbish. An understanding of gravitational waves could be useful and could help scientists find that key they need to wrap it all up.

 

Check out BICEP2’s official website:

http://www.cfa.harvard.edu/CMB/bicep2/science.html

Quantum Droplet


Quasichemistry is a branch of chemistry that studies a special type of particles called quasiparticles.

These are different from normal particles because they cannot exist individually, but only inside of solids. They act as if they were floating freely in space, with weak interactions with other particles.

For example, it is believed an electron, although a fundamental particle (the simplest substance which doesn’t have any substructure), is made of 3 quasiparticles, a holon, a spinon and an orbiton. Each of these quasiparticles has a different characteristic that codes for the electron. The holon carries the electron’s charge, the spinon its spin and the orbiton its location in the orbit.

dropleton

Named dropleton because it’s like a liquid drop

However, they are not real particles, just a mathematical tool used to simplify the way electrons and nuclei move in a specific way.

There have been many quasiparticles discovered, and they are used to explore the quantum world in more depth. So every time a new quasiparticle is discovered it’s a celebration that we are closer to understanding physics at it’s smallest level.

Recently, a new quasiparticle was created, the “dropleton” (named because it’s a quantum droplet).

The way it is created is when a short laser pulse was directed at a semiconductor made of gallium arsenide. The energy given to the material causes electrons to move, creating excitons (pairs of holes in a material because of the absence of an electron). Once there are many excitons, they start joining to electrons, and moving around the solid.

But what’s interesting is the way they travel. Normal quasiparticles move like normal particles, but the dropletons flowed, rather than moved. In fact, they behaved like a group of particles in a liquid. It’s the first quasiparticles to act in a liquid fashion.

They are also special because of their longevity. They last for 25 picoseconds, which although is extremely short period of time for us humans it is quite a long time in the quantum world. This and their size (200 nanometres) allows scientists to test them and discover more about them. Not only that, but they also form stable structures. The smallest dropleton is 4 electron-hole pairs; the biggest is 14.

Autism Hates Males


Autism is a genetic condition that affects both males and females, but a recent study suggests that women have a special protection against this disorder that men lack.

For a person to become autistic there must be a genetic mutation. Sometimes it only takes a mutation in one gene, but normally it is a group of mutations that end up causing autism. In fact, throughout the years, there’s been hundreds of mutations discovered that have the ability of causing it. But now we know that the number of genes that cause autism in humans can be different depending on gender.

This difference because of sex was found out by a group of scientists in the University Hospital of Lausanne in Switzerland, where more than 700 families with a child with autism were tested, and their genome analysed.

They were looking for two different types of mutations: copy number variations (where large parts of the genetic material is destroyed or duplicated) and single gene mutations. The conclusion was females were three times more likely to have more of these mutations than males.autism

The fact that girls have to have more mutations to contract this condition means they are more protected than men, which explains why there are 4 times as many male autistic people as there are females. So their brains can work better with mutations than men’s with the same mutations.

To back these results, there’s been another investigation, from the Autism Genome Project, with 2400 patients, which shows similar results. The aim of this foundation is to map the genome of as many autistic people as possible, so as to find a trend they could understand and translate it into a treatment for autism. Although there is still no conclusion, there is progress in this field, demonstrated by this discovery. If we were able to decipher the way in which females are protected, we could be closer to creating a cure for this condition suffered by more than tens of millions of people worldwide.

Higgs’ Roar


Celebrating the Big Bang Theory’s 50th birthday, scientists in Finland have run the first 3-dimensional simulation of the first seconds of the famous explosion, to investigate the effect the newly born Higgs field would have had, and have discovered it has loud repercussions.

The Higgs field is what gives most particles their mass, and is generated by the Higgs Boson, the last particle to be discovered in our current physics model which we use to explain the universe.

However, when the universe had just appeared, and new particles were being created with it, they didn’t have mass at first. It was only 100 picoseconds later that the Higgs field was turned on and mass appeared.

Of course, this sudden change in the composition of the universe (from having no mass at all to being filled with it), would have had a noticeable effect. It could be thought that the field started acting evenly around the universe, but a theory suggests that Higgs fields were generated in bubbles that started spreading in random areas (like bubbles in boiling water), growing and giving mass to any particles they happened to engulf.

But what happened when two bubbles collided? This is question (and the consequent answer) that has real implications.

When interacting with each other, the bubbles would have caused a disturbance in the space-time

bubbles

Higgs Fields could’ve spread around the space time tissue like bubbles

fabric, causing a series of ripples of gravitational waves, which are unfortunately too weak for us to detect. But they would’ve also released large amounts of energy to the particles, therefore creating shock waves or sonic booms. These would then be translated into low rumbles that would have subsequentially caused more gravitational waves. These two sets of waves, when joined together, could gain enough force for us to eventually detect them, although not with our current technology. We will have to wait until we develop more sensitive detectors that are capable of detecting these waves until we can finally approve this theory.

Wingardium Leviosa


Levitation has always seemed like an idea from science fiction or sorcery; never something that could be achieved otherwise. Scientists at the University of Tokyo obviously disagreed, since they have created a technology that is able to make small objects float around, using the power of sound waves.

The way they accomplished this feat was by setting up a group of four speakers, which were then set to fire sound, much like a normal speaker. The twist is that the waves were actually ultrasound, those sound frequencies that are above human hearing, and they were standing waves, which bounce back from a surface and return to their source, therefore not transferring energy.

When these waves interfered with each other, two phenomenon’s occur: the waves ‘join together’ to make an extra strong wave, or they cancel each other out. In this last case is where the interesting thing happens.

By cancelling each other, they create a tiny void (known as a node), where there is virtually no wave. So if you insert an object in this air pocket, it can be maintained there by the pressure of the waves outside it pushing it inside. What’s more; if you have 4 speakers, you can change their frequency and this will move the object in three dimensions.

However, this technology won’t be able to levitate a human being anytime soon. At the most, it can sustain an object of 4 centimetres of size. For example, in this experiment, they first used alcohol droplets, feathers and small beads.

This limitation doesn’t mean it’s a useless invention. On the contrary, with further developing, it could be used to manipulate objects in microgravity, or even making purer and more efficient drugs (by mixing them differently).

 

A video explaining how this works and some examples of its effect on different objects:

Human Cells’ Time Travel


Last week, I wrote about cells in mice turning pluripotent, meaning having the ability to turn into any cell from our body, by just dipping them in an acidic solution. The conclusion was that if converting normal, specialised cells and converting them into pluripotent cells was possible in humans, it would mean hope for studies in regenerative science and cancer research.

Well, scientists at Harvard Medical School did not waste their time and have already accomplished this feat. Using human cells this time, instead of mice cells, the team applied different environments to the cells, until they finally managed to make them behave like the mice STAP cells (Stimulus-triggered acquisition of pluripotency) they had previously created.

embryo 8

Embryo cell, with 8 totipotent cells

However, these new cells did show some differences to the original, and it’s because different solutions were used, since mice and human cells are not identical and the same solutions wouldn’t have worked. Which solutions were used still remains a secret, and it could be for the best, to prevent uncontrolled use of human pluripotent cells is not advisable.

Another drawback is the fact that these human STAP cells have not shown totipotency (the ability to form a placenta and therefore create an organism). But this could not be as bad as it looks at first sight. The use of totipotent cells at the moment is very strict and regulated, but the study of pluripotent cells not as much. So although work with human totipotent cells couldn’t be done, pluripotent cells are still very useful and worth having a look at.

Of course work still needs to be done, but we are one step closer to being able to study stem cells and the opportunities they provide. It is still a very admirable achievement from scientists at Harvard to have found this only a week after the results with mice were published.