Mother of 'Capillary Dynamolysis'
Monday, October 8, 2007
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Brain connections cause rethink over human memory
Brain connections cause rethink over human memory
From issue 2621 of New Scientist magazine, 18 September 2007, page 23
How do we store so many memories? It is a question that has puzzled neuroscientists for decades - and now it seems that our concept of how memory works may have been wrong all along.
It was originally assumed that the number of memories was proportional to the number of neurons in a network. Given that even 1 cubic centimetre of the brain's cortex contains about 50 million neurons, it seemed that the brain could indeed store masses of information. However, this model relied on the notion that each neuron is connected to every other neuron, whereas a neuron is actually connected to between 5000 and 10,000 others.
Neuroscientists then proposed that the number of memories was proportional to the number of connections per neuron. Now Yasser Roudi and Peter Latham at University College London have found a problem with this model too. They calculated that even with 10,000 connections per neuron, a network could only store about 100 memories - regardless of how many neurons were in the network (PLoS Computational Biology, DOI: 10.1371/journal.pcbi.0030141).
This implies that to store a large amount of information, the brain would have to use multiple networks. This may be problematic for something like vocabulary, Latham says. "You wouldn't want to store 100 words in each of [many] different networks; you probably want to store them more or less in one place. Now we don't know how [the brain] does this."
From issue 2621 of New Scientist magazine, 18 September 2007, page 23
How do we store so many memories? It is a question that has puzzled neuroscientists for decades - and now it seems that our concept of how memory works may have been wrong all along.
It was originally assumed that the number of memories was proportional to the number of neurons in a network. Given that even 1 cubic centimetre of the brain's cortex contains about 50 million neurons, it seemed that the brain could indeed store masses of information. However, this model relied on the notion that each neuron is connected to every other neuron, whereas a neuron is actually connected to between 5000 and 10,000 others.
Neuroscientists then proposed that the number of memories was proportional to the number of connections per neuron. Now Yasser Roudi and Peter Latham at University College London have found a problem with this model too. They calculated that even with 10,000 connections per neuron, a network could only store about 100 memories - regardless of how many neurons were in the network (PLoS Computational Biology, DOI: 10.1371/journal.pcbi.0030141).
This implies that to store a large amount of information, the brain would have to use multiple networks. This may be problematic for something like vocabulary, Latham says. "You wouldn't want to store 100 words in each of [many] different networks; you probably want to store them more or less in one place. Now we don't know how [the brain] does this."
Ketamine relieves depression within hours
Ketamine relieves depression within hours
12:57 08 August 2006
NewScientist.com news service
Roxanne Khamsi
A drug used as a general anaesthetic may also work as a remarkably rapid antidepressant, according to a preliminary study.
The drug’s hallucinogenic side effects mean it is unlikely to be prescribed to patients, but it could pave the way to new faster-acting antidepressants, the researchers suggest.
Ketamine is used as an animal tranquiliser, but is perhaps better known as an illicit street drug, sometimes called “special K”. Now researchers have found the drug can relieve depression in some patients within just 2 hours – and continue to do so for a week.
One problem with current antidepressants is that they typically take weeks to kick in. Some studies have found that patients may face a high risk of suicide in the first week after starting an antidepressant treatment because of this lag time. So researchers have been searching for alternative drugs.
Fast acting
In 2000, a small study of eight people with major depression suggested that ketamine mitigated depression to a certain degree (Biological Psychiatry, vol 47, p 351).
Carlos Zarate, chief of the Mood and Anxiety Disorders Research Unit at the National Institute of Mental Health in Bethesda, Maryland, US and colleagues, set out to conduct a larger, more detailed trial of the drug’s antidepressant effects.
They analysed data from 17 participants, all whom suffered from moderate to severe depression and had failed to respond to at least two types of conventional drug treatments....
12:57 08 August 2006
NewScientist.com news service
Roxanne Khamsi
A drug used as a general anaesthetic may also work as a remarkably rapid antidepressant, according to a preliminary study.
The drug’s hallucinogenic side effects mean it is unlikely to be prescribed to patients, but it could pave the way to new faster-acting antidepressants, the researchers suggest.
Ketamine is used as an animal tranquiliser, but is perhaps better known as an illicit street drug, sometimes called “special K”. Now researchers have found the drug can relieve depression in some patients within just 2 hours – and continue to do so for a week.
One problem with current antidepressants is that they typically take weeks to kick in. Some studies have found that patients may face a high risk of suicide in the first week after starting an antidepressant treatment because of this lag time. So researchers have been searching for alternative drugs.
Fast acting
In 2000, a small study of eight people with major depression suggested that ketamine mitigated depression to a certain degree (Biological Psychiatry, vol 47, p 351).
Carlos Zarate, chief of the Mood and Anxiety Disorders Research Unit at the National Institute of Mental Health in Bethesda, Maryland, US and colleagues, set out to conduct a larger, more detailed trial of the drug’s antidepressant effects.
They analysed data from 17 participants, all whom suffered from moderate to severe depression and had failed to respond to at least two types of conventional drug treatments....
New drugs could spell quick fix for depression
New drugs could spell quick fix for depression
From issue 2620 of New Scientist magazine, 08 September 2007, page 21
SNAPPING out of depression is easier said than done.
Antidepressants such as selective serotonin reuptake inhibitors (SSRIs) can take several weeks to kick in, and for some patients there is an urgent need for a faster-acting drug. Now Guillaume Lucas at McGill University in Montreal, Canada, and his team have found a class of antidepressants that reverse symptoms of depression in rats within days.
The drug, RS67333, works by binding to a receptor on the surface of brain cells and stimulating them to release more serotonin, a neurotransmitter that helps control mood.
Rats with symptoms of depression returned to normal after just three days of injections with the drug, while those treated with a standard SSRI took two weeks to recover (Neuron, DOI: 10.1016/j.neuron.2007.07.041).
From issue 2620 of New Scientist magazine, 08 September 2007, page 21
SNAPPING out of depression is easier said than done.
Antidepressants such as selective serotonin reuptake inhibitors (SSRIs) can take several weeks to kick in, and for some patients there is an urgent need for a faster-acting drug. Now Guillaume Lucas at McGill University in Montreal, Canada, and his team have found a class of antidepressants that reverse symptoms of depression in rats within days.
The drug, RS67333, works by binding to a receptor on the surface of brain cells and stimulating them to release more serotonin, a neurotransmitter that helps control mood.
Rats with symptoms of depression returned to normal after just three days of injections with the drug, while those treated with a standard SSRI took two weeks to recover (Neuron, DOI: 10.1016/j.neuron.2007.07.041).
Biofuel made from power plant CO2
Biofuel made from power plant CO2
New Scientist
06 October 2006
Phil Mckenna
Magazine issue 2572
"If you're working at a power plant, you just saw your carbon dioxide turned into something you can drive home with." So says Isaac Berzin of GreenFuel Technologies in Cambridge, Massachusetts, which is developing a way of producing biofuel from the noxious emissions of power plants.
Two of the world's greatest energy users are electricity generation and transport. Both are responsible for huge quantities of greenhouse gas emissions, as most power plants and vehicles still rely on fossil fuels. Now GreenFuel and others are hoping to marry the two together with an emerging technology that uses a by-product of one to supply fuel to the other. Doing so could dramatically reduce their overall carbon dioxide emissions.
At the heart of the technology is a plastic cylinder full of algae, which literally sucks the CO2 out of a power plant's exhaust. The algae can in turn be converted into biofuel, creating ...
New Scientist
06 October 2006
Phil Mckenna
Magazine issue 2572
"If you're working at a power plant, you just saw your carbon dioxide turned into something you can drive home with." So says Isaac Berzin of GreenFuel Technologies in Cambridge, Massachusetts, which is developing a way of producing biofuel from the noxious emissions of power plants.
Two of the world's greatest energy users are electricity generation and transport. Both are responsible for huge quantities of greenhouse gas emissions, as most power plants and vehicles still rely on fossil fuels. Now GreenFuel and others are hoping to marry the two together with an emerging technology that uses a by-product of one to supply fuel to the other. Doing so could dramatically reduce their overall carbon dioxide emissions.
At the heart of the technology is a plastic cylinder full of algae, which literally sucks the CO2 out of a power plant's exhaust. The algae can in turn be converted into biofuel, creating ...
Artificial soil: quick and dirty
Artificial soil: quick and dirty
New Scientist
13 August 2007
Jessica Marshall
Magazine issue 2616
YOU might think it's as common as muck. Dirt cheap, even. In fact, the soil beneath our feet is anything but. Good, fertile topsoil is crucial for 97 per cent of the world's food supply, and without it parks and gardens would look more brown than green. So it's a worry that soil has joined the long list of resources that are beginning to run out - and there is no natural way to replace it in our lifetime. But soon there might be. By mixing together a bit of animal, vegetable and mineral, researchers are turning waste into fertile ground.
Making soil is a complicated business. In nature it develops when weathered rock and decomposing plant and animal material are mixed and broken down by plant roots, soil fauna, microbes and fungi. Over hundreds of years, if the chemical and biological mix is right, the raw ingredients are ...
... Others are trying similar approaches. Richard Haynes at the University of Queensland, Australia, is trialling a mix of fly ash and chicken litter, composted together with tree and garden waste, as part of a government and industry-sponsored effort to turn waste into new soil. ...
New Scientist
13 August 2007
Jessica Marshall
Magazine issue 2616
YOU might think it's as common as muck. Dirt cheap, even. In fact, the soil beneath our feet is anything but. Good, fertile topsoil is crucial for 97 per cent of the world's food supply, and without it parks and gardens would look more brown than green. So it's a worry that soil has joined the long list of resources that are beginning to run out - and there is no natural way to replace it in our lifetime. But soon there might be. By mixing together a bit of animal, vegetable and mineral, researchers are turning waste into fertile ground.
Making soil is a complicated business. In nature it develops when weathered rock and decomposing plant and animal material are mixed and broken down by plant roots, soil fauna, microbes and fungi. Over hundreds of years, if the chemical and biological mix is right, the raw ingredients are ...
... Others are trying similar approaches. Richard Haynes at the University of Queensland, Australia, is trialling a mix of fly ash and chicken litter, composted together with tree and garden waste, as part of a government and industry-sponsored effort to turn waste into new soil. ...
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