Monday, May 31, 2010
Sunday, May 30, 2010
As Jane Marple is celebrating its 25th anniversary this spring, it is also another famous name celebrating an anniversary - 10 years, it’s not that bad - LAMP Harajuku which is ravishing our eyes with a revisited fashion inspired by 60’s and – believe it or not – a Czechoslovakian movie. Located between Omotesando and Harajuku Station, LAMP Harajuku will guide your shopping into their house looking-like shop, where you would stay all day long...
Saturday, May 29, 2010
Friday, May 28, 2010
Hemopressin is a small protein that was discovered in the brains of rodents in 2003: its name comes from the fact that it's a breakdown product of hemoglobin and that it can lower blood pressure.
No-one seems to have looked to see whether hemopressin is found in humans, yet, but it seems very likely. Almost everything that's in your brain is in a mouse's brain, and vice versa.
Pharmacologically, hemopressin's literally an anti-marijuana molecule: it's an inverse agonist at CB1 receptors, which are the ones targeted by the psychoactive compounds in marijuana, and also by the neurotransmitters known as endocannabinoids. Cannabinoids turn CB1 receptors on, hemopressin turns them off.
Artificial CB1 blockers were developed as weight loss drugs, and one of them, rimonabant, made it onto the market - but it was banned after it turned out that it caused depression and anxiety in many people.
So hemopressin is Nature's rimonabant: in which case, it ought to do what rimonabant does, which is to reduce appetite. And indeed a Journal of Neuroscience paper just out from Godd et al shows that it does just that, in rats and mice: injections of hemopressin reduced feeding.
Interestingly, this worked even when it was injected by the standard route under the skin - many proteins can't enter the brain if they're given this way, because they can't cross the blood-brain barrier, meaning that they have to be injected directly into the brain, which makes researching them much harder. So hemopressin, with any luck, will be pretty easy to study. Any volunteers for the first human trial...?
Dodd, G., Mancini, G., Lutz, B., & Luckman, S. (2010). The Peptide Hemopressin Acts through CB1 Cannabinoid Receptors to Reduce Food Intake in Rats and Mice Journal of Neuroscience, 30 (21), 7369-7376 DOI: 10.1523/JNEUROSCI.5455-09.2010
Thursday, May 27, 2010
DNA is a series of bases, and fundamentally there are just four: C, A, T and G. However, the Cs and the As can be methylated, i.e. modified by the addition of a very simple methyl chemical group. They then stay that way until they get demethylated in the reverse process. Methylating a gene generally reduces its expression.
It's a bit like writing notes in pencil on top of a printed document: it doesn't change the underlying genetic sequence, but it's a semi-permanent change and it can be inherited by dividing cells. Methylation is a classic example of an epigenetic change, and epigenetics is very hot right now.Miller et al found that learning induces the methylation of a gene called calcineurin (CaN) in the cells of the frontal cortex of rats. These changes appeared within 1 day of the learning event, and they persisted for at least 30 days (the longest time studied - they could well last much longer). Methylation of another gene, reelin, was also increased, but only for a few hours.
When they blocked these changes by injecting a DNA methylation inhibitor into the frontal cortex, it caused amnesia - even if the drug was given 30 days after the learning had taken place. In other words, the methylation inhibitors somehow erased the memory traces. These authors have previously reported that the same kind of learning causes a short-lived increase in methylation in the hippocampus. Taken together with these data, this fits with the well-known theory that memory traces start off being stored in the hippocampus and are then somehow transferred to the cortex later.
This kind of research has a bit of a history. The idea that memories are stored in DNA has led some to theorize that memories can be inherited. It also reminds me of the work of psychologist and Unabomber-victim James McConnell, who claimed that planarian worms can learn information by eating the ground-up remains of other worms who knew something...
These data are very interesting, but they don't imply anything quite so exciting. The pattern of methylation seemed entirely random (except in the sense that it was targeted at certain genes) - so rather than encoding information per se, the DNA changes were acting as a way of reducing CaN gene expression. Most likely, the reduction in CaN was limited to certain cells, and these were the cells that formed the connections that encoded the information.
Miller, C., Gavin, C., White, J., Parrish, R., Honasoge, A., Yancey, C., Rivera, I., Rubio, M., Rumbaugh, G., & Sweatt, J. (2010). Cortical DNA methylation maintains remote memory Nature Neuroscience, 13 (6), 664-666 DOI: 10.1038/nn.2560
The author of one of our favorite music apps for Facebook,Muziic, is back with a new app that brings some pizazz to your YouTube music listening sessions. Muziic DJ is a web application that turns YouTube into a virtual DJ studio, enabling you to create playlists and mix the tracks into a seamless party mix.
The app lets you search YouTube for tracks and albums, which you can play in two virtual “decks” or save as playlists for later. Features such as Auto DJ (which automatically switches to the next track) and crossfade make the DJ-ing experience quite enjoyable. The app also supports some simple effects such as “brake” and “reverb,” as well as additional loops and sounds you can play over the songs.
Wednesday, May 26, 2010
But away from the protests, Britons have many quality establishments in the country from which to choose, while a British-style education is increasingly sought-after by Thais themselves. All featured schools take pupils from the early years through to 18.
Schools covered in the report are:
- Bangkok Pattana School
- Harrow International School, Bangkok
- The Regent's School Pattaya
- Shrewsbury International School, Bangkok
Go to telegraph.co.uk for full article.
Tuesday, May 25, 2010
A Briton arrested in Thailand faces years in jail, or even a death sentence, for urging redshirt rioters to burn down a shopping centre.
Jeff Savage, a 48-year-old married man, originally from Tonbridge in Kent, has been accused by Thailand's prime minister of being a long-time member of the anti-government redshirt movement and a key agitator in the riots which saw swaths of the capital burn last week.
In his first prison interview since being arrested on Sunday, Savage, who has lived in Thailand for nine years, told the Guardian he was being fitted up for crimes he did not commit. He denied he was involved in burning down the Central World shopping centre in the heart of Bangkok's shopping district.
"I am being stitched up, being fitted up. I thought it was just for overstaying my visa, but now this is serious," Savage said from behind bars in Bangkok remand prison.
The drink is the equivalent of eating 13 McDonald's Baked Hot Apple Pies.
- Search for a phone that suits you.
- Choose from over 40 different features.
- Specify price range to narrow down results.
- Restrict results by entering a model name.
- No registration required.
- Similar tools: TryPhone
Monday, May 24, 2010
So - everyone knows that fMRI is a way of measuring neural activation. But what does it mean for a neuron to be active? All brain cells are "active": they're alive, firing electrical action potentials, and sending out neurotransmitters to other cells at synapses. If a certain cell gets more activated, that means that it's firing action potentials faster, or sending out more chemical signals. It's mostly synaptic activity which fMRI picks up.
How do you measure neural activation? You can do it directly by sticking in an electrode to measure action potentials, or use a glass tube to measure neurotransmitter levels. You can put electrodes on the scalp to pick up the electrical fields created by lots of neurons firing. But fMRI relies on an indirect approach: when a brain cell is firing hard, it uses more energy than when it's not.
Cells make energy from sugar and oxygen; oxygen is transported in the blood. So when a given cell is working hard, it uses more oxygen, and the oxygen content of nearby blood falls. Synaptic activity, in particular, uses loads of oxygen. So you might expect that highly active parts of the brain would have less oxygen. Counter-intuitively, they actually show an increase in blood oxygen, which is probably a kind of "overcompensation" for the activity (although there may be an "initial dip" in oxygen, it's very brief.)
So blood oxygen is a proxy for activation. How do you measure it? Oxygen in blood binds to haemoglobin, a protein that contains iron (which is why blood is red, like rust, and tastes metallic...like iron). By a nice coincidence, haemoglobin with oxygen is red; haemoglobin without oxygen is blueish or purple. This is why your veins, containing deoxygenated blood, are blue and why you turn blue if you're suffocating.
You could measure neural activity by literally looking to see how red the brain is. This is actually possible, but obviously it's a bit impractical. Luckily, as well as being blue, deoxygenated haemoglobin acts as a magnet. So blood is magnetic, and the strength of its magnetic field depends on how oxygenated it is. That's really useful, but how do you measure those magnetic fields?
Using an extremely strong magnet - like the liquid-helium-cooled superconducting coil at the heart of every MRI scanner, for example - you can make some of the protons in the body align in a special way. If you then fire some radio waves at these aligned protons, they can absorb them ("resonate"). As soon as you stop the radio waves, they'll release them back at you, like an echo - which is why the most common form of fMRI scan is called Echo-Planar Imaging (EPI). All matter contains protons; in the human body, most of them are found in water.
Each proton only responds to a specific frequency of radio waves. This frequency is determined by the strength of the magnetic field in which it sits - stronger fields, higher frequencies. Crucially, the magnetic fields surrounding deoxygenated blood therefore shift the radio frequency at which nearby protons respond. Suppose a certain bit of the brain resonates at frequency X. If some deoxygenated blood appears nearby, it will stop them from responding to that frequency - by making them respond to a different one.
fMRI is essentially a way of measuring the degree to which protons in each part of the brain don't respond at the "expected" resonant frequency X, due to interference from nearby deoxygenated haemoglobin. But how do you know what resonant frequency to expect? This is the clever bit: simply by varying the magnetic field across different parts of the brain.
Say you make the magnetic field at the left side of the head slightly stronger than the one at the right - a magnetic gradient. The resonant frequency will therefore vary across the head: the further left, the higher the frequency. This is what the "gradient coils" in an MRI machine do.
Gradient coils therefore translate spatial location into magnetic field strength. And as we know, magnetic field strength = resonant frequency. So spatial location = magnetic field strength = resonant frequency. All you then need to do is to hit the brain with a burst of radio waves of all different frequencies - a kind of white noise called the "RF Pulse" - and record the waves you get back.
The strength of the radio waves at a given frequency therefore corresponds to the amount of protons in the appropriate place - so you can work out the density of matter in the brain based on the frequencies you get. Also, different kinds of tissues in the body respond differently to excitation; bone responds differently to brain grey matter, for example. So you can build up an image of brain structure by using magnetic gradients.
Of course you can't scan the whole brain at once: you scan it in slices, divided up into roughly cubic units called voxels. Typically in fMRI these are 3x3x3 mm or so, but they can be much smaller for specialized applications. The smaller the voxels, the longer the scan takes because it requires more gradient shifting. The loud noises that occur during MRI scans are caused by the gradient coils changing the gradients extremely quickly in order to scan the whole brain. Modern scanners typically image the whole brain once every 3 seconds, but you can go even faster.
As we've seen, deoxygenated blood degrades the image nearby, in what's called the Blood Oxygenation Level Dependent (BOLD) response. Neural activation increases oxygen and literally makes the brain light up; you could, in theory, see the changes with the naked eye. In fact, they're tiny, and there is always a lot of background noise as well, so you need statistical analysis to determine which parts light up, and then map this onto the brain as colored blobs. But that's another story...
- 5 x picture resolution (program prroviders will upscale non hi-def material)
- Dolby Digital surround (selected programs only)
- Wide screen 16:9 aspect ratio
The Hi-Def service is for Platinum and Gold subscribers only.
On a Thai language poster advertising the service it looked to me as if the cost of the Hi-Def service is an extra Bt590/- per month which I guess is for the digital decoder. Don't hold me to this as my Thai language skills are basic, If you are interested in Hi-Def , please phone 02-7252525 or call in to your local Truevisions shop to see a demo of the Hi-Def service.
Saturday, May 22, 2010
Friday, May 21, 2010
Thursday, May 20, 2010
Small investors, married couples, motorists and holidaymakers are likely to be hit with tax rises under plans unveiled by the coalition Government. Cameron confirmed that the coalition Government would push ahead with plans to increase sharply capital gains tax on the sale of second homes, shares and buy-to-let properties.
More money is expected to be raised by changing the way flights are taxed, which could add more than £300 to the cost of a long-haul family
Author: Valerie Fujita