Top ten breakthroughs of the year
The one that tops the list of
breakthroughs this year is the finding of the human genetic variation. We have
come
a long way from asking what in our DNA makes us human to striving to know what
in my DNA makes me me.
Already, the genomes of several individuals have been sequenced, and rapid
improvements in sequencing technologies are making the sequencing of "me" a real
possibility.
The potential to quantify one's genetic risk for cancer, asthma, or diabetes -
is both exhilarating and terrifying.
It comes not only with great promise for improving health through personalized
medicine and understanding our individuality but also with risks for
discrimination
and loss of privacy.
Reprogramming cells
What is it about the oocyte that rejuvenates the nucleus of a differentiated
cell, prompting the genome to return to the embryonic state and form a new
individual?
In a series of papers, researchers showed that by adding just a handful of
genes to skin cells, they could reprogram those cells to look and act like
embryonic
stem (ES) cells. ES cells are famous for their potential to become any kind of
cell in the body.
In June this year, in two announcements that electrified the stem cell field, a
Japanese group, along with two American groups, showed that the iPS cells
made from mouse skin could, like ES cells, contribute to chimeric embryos and
produce all the body's cells, including eggs and sperm.
The work convinced most observers that iPS cells were indeed equivalent to ES
cells, at least in mice. Then in November came a triumph no one had expected
this soon: Not one, but two teams repeated the feat in human cells.
In December, scientists reported that they had already used mouse iPS cells to
successfully treat a mouse model of sickle cell anaemia.
Tracing cosmic bullets
What's smaller than an atom but crashes into Earth with as much energy as a
golf ball hitting a fairway? Since the 1960s, that riddle has tantalized
physicists
studying the highest energy cosmic rays, particles from space that strike the
atmosphere with energies 100 million times higher than particle accelerators
have reached. This year, the Pierre Auger Observatory in Argentina supplied key
clues to determine where in space the interlopers come from.
On their long trips, protons loss their energy and leaves few with more than 60
EeV. So the excess suggested that the rays might be born in our galactic
neighbourhood. But researchers with the Hi-Res detector in Dugway, Utah, saw
only two 100-EeV rays, about as many as expected from far-off sources.
Last month, the Auger team reported that they seem to emanate from active
galactic nuclei (AGNs): enormous black holes in the middles of some galaxies.
The AGNs lie within 250 million light-years of Earth, close enough that cosmic
radiation would not have drained the particles' energy en route.
Auger researchers haven't yet proved that AGNs are the sources of the rays, and
no one knows how an AGN might accelerate a proton to such stupendous energies.
Receptor visions
Just when some crystallographers were fretting that the task was impossible,
researchers nabbed a close-up of adrenaline's target, the beta 2-adrenergic
receptor. Its structure has long been on the to-do list.
The receptor is one of roughly 1000 membrane-spanning molecules called G
protein-coupled receptors (GPCRs). By detecting light, odours, and tastes, the
receptors clue us in to our surroundings.
>From antihistamines to beta blockers, the pharmacopoeia brims with medicines
>aimed at GPCRs - all of which researchers discovered without the benefit of
high-resolution structures. A clear picture of, say, a receptor's binding site
might spur development of more potent, safer drugs. But scientists had cracked
only one "easy" GPCR structure, for the visual pigment rhodopsin.
Getting a look at the receptor took the leaders of two overlapping
crystallographic teams almost 2 decades. The effort paid off this fall with
four papers
published in the journals Science, Nature, and Nature Methods.
Beyond silicon?
Sixty years ago, semiconductors were a scientific curiosity. Then researchers
tried putting one type of semiconductor up against another, and suddenly we
had diodes, transistors, microprocessors, and the whole electronic age.
Startling results this year may herald a similar burst of discoveries at the
interfaces
of a different class of materials: transition metal oxides.
Transition metal oxides first made headlines in 1986 with the Nobel
Prize-winning discovery of high-temperature superconductors. Since then,
solid-state
physicists keep finding unexpected properties in these materials. But the fun
should really start when one oxide rubs shoulders with another.
If different oxide crystals are grown in layers with sharp interfaces, the
effect of one crystal structure on another can shift the positions of atoms at
the interface, alter the population of electrons, and even change how
electrons' charges are distributed around an atom.
Teams have grown together two insulating oxides to produce an interface that
conducts like a metal or, in another example, a superconductor.
Electrons take a new spin
Theoretical physicists in California recently predicted that semiconductor
sandwiches with thin layers of mercury telluride (HgTe) in the middle should
exhibit an unusual behavior of their electrons called the quantum spin Hall
effect (QSHE). This year, they found just what they were looking for.
The effect is the latest in a series of oddball ways electrons behave when
placed in external electric and magnetic fields. In 1980, researchers in Germany
and the U.K. discovered one of these anomalies, called the quantum Hall effect.
When they changed the strength of a magnetic field applied perpendicular to
charges moving through thin layers of metals or semiconductors, they found that
the conductance changed in a stepwise, or quantized, manner.
One upshot was that charges flowed in tiny channels along the edges of the
materials with essentially no energy loss. The finding triggered hopes of new
families of computer chip devices.
In recent years, theorists have predicted that materials with the right
electronic structure should interact with electric fields to result in the QSHE
- and a spin-driven version of near-lossless conduction.
Such materials would also do away with the need for high magnetic fields and
perhaps even for low temperatures. If researchers can do the same trick at
room temperature, the discovery could open the door to new low-power
"spintronic" computing devices that manipulate electrons by both charge and
spin.
Divide to conquer
Fresh evidence illuminating how immune cells specialize for immediate or
long-term protection had researchers a little feverish this year. When a
pathogen
attacks, some CD8 T cells become short-lived soldiers, while others morph into
memory cells that loiter for decades in case the same interloper tries again.
The new work demonstrates how one cell can spawn both cell types.
A T cell remains passive until it meets a dendritic cell carrying specific
pathogen molecules. As the cells dally, receptors and other molecules congregate
at each end of the T cell. A U.S.-based team tested the proposal that if the T
cell then divided, its progeny would inherit different molecules that might
steer them onto distinct paths.
In March, the team reported experiments showing that different
specialization-controlling proteins amassed at each pole of a T cell during its
dance with
a dendritic cell. When the researchers nabbed newly divided T cells, they found
that progeny that had been adjacent to the dendritic cell carried receptors
typical of soldiers, whereas their counterparts showed the molecular signature
of memory cells. Unequal divisions could also help generate diversity among
CD4 T cells, immune regulators that differentiate into three types. Practical
applications of the discovery will have to wait until researchers know more
about memory-cell specialization.
Doing more with less
Society may finally be embracing energy efficiency and waste reduction. Extra
stature go to chemists who carry out desired reactions in the simplest and
most elegant ways.
This year chemists showed that they are gaining a new level of control over the
molecules they make and how they make them.
When chemists convert a starting compound into one they really want, they
typically aim to modify just one of those appendages but not the others.
One group in Israel used a ruthenium-based catalyst to convert starting
compounds called amines and alcohols directly into another class of widely
useful
compounds called amides. A related approach enabled researchers in Canada to
link pairs of ring-shaped compounds together. Another minimized the use of
protecting groups to make large drug-like organic compounds. Yet another did
much the same in mimicking the way microbes synthesize large ladder-shaped
toxins. And those are just a few examples. For chemists, it was an efficient
year.
Back to the future
Remembering the past, they propose, helps us picture - and prepare for -the
future. The notion got a boost this year from several studies hinting at common
neural mechanisms for memory and imagination.
In January, researchers in the United Kingdom reported that five people with
amnesia caused by damage to the hippocampus, a crucial memory center in the
brain, were less adept than healthy volunteers at envisioning hypothetical
situations. In April, a brain-imaging study with healthy young volunteers found
that recalling past life experiences and imagining future experiences activated
a similar network of brain regions, including the hippocampus. Even studies
with rats suggested that the hippocampus may have a role in envisioning the
future.
On the basis of such findings, some researchers propose that the brain's memory
systems may splice together remembered fragments of past events to construct
possible futures. The idea is far from proven, but if future experiments bear
it out, memory may indeed turn out to be the mother of imagination.
Game over
Computer scientists finally took some of the fun out of the game of checkers.
After 18 years of trying, a Canadian team proved that if neither player makes
a mistake, a game of checkers will inevitably end in a draw.
The proof makes checkers - also known as draughts - the most complicated game
ever 'solved.' It marks another victory for machines over humans.
Proving that flawless checkers will end in a stalemate was hardly child's play.
The game is played on an eight-by-eight grid of red and black squares. All
told, there are about 500 billion billion arrangements of the pieces, enough to
overwhelm even today's best computers.
So the researchers compiled a database of the mere 39,000 billion arrangements
of 10 or fewer pieces and determined which ones led to a win for red, a win
for black, or a draw. They then considered a specific opening move and used a
search algorithm to show that players with perfect foresight would invariably
guide the game to a configuration that yields a draw.
Reported in July, the advance exemplifies an emerging trend in artificial
intelligence.
ELIZABETH PENNISI
AND NEWS STAFF
SCIENCE JOURNAL
The one that tops the list of
breakthroughs this year is the finding of the human genetic variation. We have
come
a long way from asking what in our DNA makes us human to striving to know what
in my DNA makes me me.
Already, the genomes of several individuals have been sequenced, and rapid
improvements in sequencing technologies are making the sequencing of "me" a real
possibility.
The potential to quantify one's genetic risk for cancer, asthma, or diabetes -
is both exhilarating and terrifying.
It comes not only with great promise for improving health through personalized
medicine and understanding our individuality but also with risks for
discrimination
and loss of privacy.
Reprogramming cells
What is it about the oocyte that rejuvenates the nucleus of a differentiated
cell, prompting the genome to return to the embryonic state and form a new
individual?
In a series of papers, researchers showed that by adding just a handful of
genes to skin cells, they could reprogram those cells to look and act like
embryonic
stem (ES) cells. ES cells are famous for their potential to become any kind of
cell in the body.
In June this year, in two announcements that electrified the stem cell field, a
Japanese group, along with two American groups, showed that the iPS cells
made from mouse skin could, like ES cells, contribute to chimeric embryos and
produce all the body's cells, including eggs and sperm.
The work convinced most observers that iPS cells were indeed equivalent to ES
cells, at least in mice. Then in November came a triumph no one had expected
this soon: Not one, but two teams repeated the feat in human cells.
In December, scientists reported that they had already used mouse iPS cells to
successfully treat a mouse model of sickle cell anaemia.
Tracing cosmic bullets
What's smaller than an atom but crashes into Earth with as much energy as a
golf ball hitting a fairway? Since the 1960s, that riddle has tantalized
physicists
studying the highest energy cosmic rays, particles from space that strike the
atmosphere with energies 100 million times higher than particle accelerators
have reached. This year, the Pierre Auger Observatory in Argentina supplied key
clues to determine where in space the interlopers come from.
On their long trips, protons loss their energy and leaves few with more than 60
EeV. So the excess suggested that the rays might be born in our galactic
neighbourhood. But researchers with the Hi-Res detector in Dugway, Utah, saw
only two 100-EeV rays, about as many as expected from far-off sources.
Last month, the Auger team reported that they seem to emanate from active
galactic nuclei (AGNs): enormous black holes in the middles of some galaxies.
The AGNs lie within 250 million light-years of Earth, close enough that cosmic
radiation would not have drained the particles' energy en route.
Auger researchers haven't yet proved that AGNs are the sources of the rays, and
no one knows how an AGN might accelerate a proton to such stupendous energies.
Receptor visions
Just when some crystallographers were fretting that the task was impossible,
researchers nabbed a close-up of adrenaline's target, the beta 2-adrenergic
receptor. Its structure has long been on the to-do list.
The receptor is one of roughly 1000 membrane-spanning molecules called G
protein-coupled receptors (GPCRs). By detecting light, odours, and tastes, the
receptors clue us in to our surroundings.
>From antihistamines to beta blockers, the pharmacopoeia brims with medicines
>aimed at GPCRs - all of which researchers discovered without the benefit of
high-resolution structures. A clear picture of, say, a receptor's binding site
might spur development of more potent, safer drugs. But scientists had cracked
only one "easy" GPCR structure, for the visual pigment rhodopsin.
Getting a look at the receptor took the leaders of two overlapping
crystallographic teams almost 2 decades. The effort paid off this fall with
four papers
published in the journals Science, Nature, and Nature Methods.
Beyond silicon?
Sixty years ago, semiconductors were a scientific curiosity. Then researchers
tried putting one type of semiconductor up against another, and suddenly we
had diodes, transistors, microprocessors, and the whole electronic age.
Startling results this year may herald a similar burst of discoveries at the
interfaces
of a different class of materials: transition metal oxides.
Transition metal oxides first made headlines in 1986 with the Nobel
Prize-winning discovery of high-temperature superconductors. Since then,
solid-state
physicists keep finding unexpected properties in these materials. But the fun
should really start when one oxide rubs shoulders with another.
If different oxide crystals are grown in layers with sharp interfaces, the
effect of one crystal structure on another can shift the positions of atoms at
the interface, alter the population of electrons, and even change how
electrons' charges are distributed around an atom.
Teams have grown together two insulating oxides to produce an interface that
conducts like a metal or, in another example, a superconductor.
Electrons take a new spin
Theoretical physicists in California recently predicted that semiconductor
sandwiches with thin layers of mercury telluride (HgTe) in the middle should
exhibit an unusual behavior of their electrons called the quantum spin Hall
effect (QSHE). This year, they found just what they were looking for.
The effect is the latest in a series of oddball ways electrons behave when
placed in external electric and magnetic fields. In 1980, researchers in Germany
and the U.K. discovered one of these anomalies, called the quantum Hall effect.
When they changed the strength of a magnetic field applied perpendicular to
charges moving through thin layers of metals or semiconductors, they found that
the conductance changed in a stepwise, or quantized, manner.
One upshot was that charges flowed in tiny channels along the edges of the
materials with essentially no energy loss. The finding triggered hopes of new
families of computer chip devices.
In recent years, theorists have predicted that materials with the right
electronic structure should interact with electric fields to result in the QSHE
- and a spin-driven version of near-lossless conduction.
Such materials would also do away with the need for high magnetic fields and
perhaps even for low temperatures. If researchers can do the same trick at
room temperature, the discovery could open the door to new low-power
"spintronic" computing devices that manipulate electrons by both charge and
spin.
Divide to conquer
Fresh evidence illuminating how immune cells specialize for immediate or
long-term protection had researchers a little feverish this year. When a
pathogen
attacks, some CD8 T cells become short-lived soldiers, while others morph into
memory cells that loiter for decades in case the same interloper tries again.
The new work demonstrates how one cell can spawn both cell types.
A T cell remains passive until it meets a dendritic cell carrying specific
pathogen molecules. As the cells dally, receptors and other molecules congregate
at each end of the T cell. A U.S.-based team tested the proposal that if the T
cell then divided, its progeny would inherit different molecules that might
steer them onto distinct paths.
In March, the team reported experiments showing that different
specialization-controlling proteins amassed at each pole of a T cell during its
dance with
a dendritic cell. When the researchers nabbed newly divided T cells, they found
that progeny that had been adjacent to the dendritic cell carried receptors
typical of soldiers, whereas their counterparts showed the molecular signature
of memory cells. Unequal divisions could also help generate diversity among
CD4 T cells, immune regulators that differentiate into three types. Practical
applications of the discovery will have to wait until researchers know more
about memory-cell specialization.
Doing more with less
Society may finally be embracing energy efficiency and waste reduction. Extra
stature go to chemists who carry out desired reactions in the simplest and
most elegant ways.
This year chemists showed that they are gaining a new level of control over the
molecules they make and how they make them.
When chemists convert a starting compound into one they really want, they
typically aim to modify just one of those appendages but not the others.
One group in Israel used a ruthenium-based catalyst to convert starting
compounds called amines and alcohols directly into another class of widely
useful
compounds called amides. A related approach enabled researchers in Canada to
link pairs of ring-shaped compounds together. Another minimized the use of
protecting groups to make large drug-like organic compounds. Yet another did
much the same in mimicking the way microbes synthesize large ladder-shaped
toxins. And those are just a few examples. For chemists, it was an efficient
year.
Back to the future
Remembering the past, they propose, helps us picture - and prepare for -the
future. The notion got a boost this year from several studies hinting at common
neural mechanisms for memory and imagination.
In January, researchers in the United Kingdom reported that five people with
amnesia caused by damage to the hippocampus, a crucial memory center in the
brain, were less adept than healthy volunteers at envisioning hypothetical
situations. In April, a brain-imaging study with healthy young volunteers found
that recalling past life experiences and imagining future experiences activated
a similar network of brain regions, including the hippocampus. Even studies
with rats suggested that the hippocampus may have a role in envisioning the
future.
On the basis of such findings, some researchers propose that the brain's memory
systems may splice together remembered fragments of past events to construct
possible futures. The idea is far from proven, but if future experiments bear
it out, memory may indeed turn out to be the mother of imagination.
Game over
Computer scientists finally took some of the fun out of the game of checkers.
After 18 years of trying, a Canadian team proved that if neither player makes
a mistake, a game of checkers will inevitably end in a draw.
The proof makes checkers - also known as draughts - the most complicated game
ever 'solved.' It marks another victory for machines over humans.
Proving that flawless checkers will end in a stalemate was hardly child's play.
The game is played on an eight-by-eight grid of red and black squares. All
told, there are about 500 billion billion arrangements of the pieces, enough to
overwhelm even today's best computers.
So the researchers compiled a database of the mere 39,000 billion arrangements
of 10 or fewer pieces and determined which ones led to a win for red, a win
for black, or a draw. They then considered a specific opening move and used a
search algorithm to show that players with perfect foresight would invariably
guide the game to a configuration that yields a draw.
Reported in July, the advance exemplifies an emerging trend in artificial
intelligence.
ELIZABETH PENNISI
AND NEWS STAFF
SCIENCE JOURNAL
________________________________
Notice: The information contained in this e-mail
message and/or attachments to it may contain
confidential or privileged information. If you are
not the intended recipient, any dissemination, use,
review, distribution, printing or copying of the
information contained in this e-mail message
and/or attachments to it are strictly prohibited. If
you have received this communication in error,
please notify us by reply e-mail or telephone and
immediately and permanently delete the message
and any attachments. Thank you
To unsubscribe send a message to [EMAIL PROTECTED] with the subject unsubscribe.
To change your subscription to digest mode or make any other changes, please
visit the list home page at
http://accessindia.org.in/mailman/listinfo/accessindia_accessindia.org.in
