Monday, May 9, 2011

May the Fourth be with You!

As many science fiction fans out there already know, today is known as Star Wars Day. May 4 is a date that makes a clever wordplay on the popular movie quote, so fans everywhere are telling their friends, "May the Fourth be with you."

We at decided to take a look at the climates on the many different locations in the Star Wars Universe.

For those of you who want a comparison to the weather in your backyard to the weather in the Star Wars Universe, there is a website to help you. The Star Wars Weather Forecast takes your current location and weather conditions and compares it to a number of different places.

For example, the weather in Anchorage this morning was a lot like Hoth, an ice-covered desolate planet that many of you can remember from "Star Wars Episode V: The Empire Strikes" back.

Han Solo famously said, "There isn't enough life on this ice cube to fill a space cruiser!" (No offense to the people of Anchorage, of course, which measured a low of 37 F).

Much farther south, the weather in Belize City is a lot like that of Yavin 4, a moon home to important events in the Star Wars films. Temperatures were near 80 degrees this morning with clouds in the air.

Appropriately, the real-life location of Yavin 4 was filmed not too far away from Belize City. The ancient Mayan city of Tikal was used as the backdrop.

Meanwhile, Cairo is a lot like Tatooine today, measuring temps in the 90s today. Tatooine is an integral planet in the Star Wars universe, home to both Anakin and Luke Skywalker and known for its hot, dry climate. C-3PO referred to the planet as a "desolate place" in "Star Wars Episode IV: A New Hope."

The Sahara Desert, specifically Tunisia, was the filming location for most of Tatooine, although on this day, Tunisia is a bit too cloudy to be like the fictional planet it is based on.

Paris has the honor of being like Naboo today, a lush planet with dry, temperate weather.

According to Wookieepedia, the go-to resource for all things Star Wars, there are a number of weather-related entries. Gravel storms and dust storms are weather events common to Tatooine, while Jedi's Fire is an "electrostatic discharge that lit the sky in unusual patterns." This could be an allusion to lightning or even St. Elmo's Fire on our planet.


A Cure for Age-Related Macular Degeneration?

Until now, patients who suffer from one of the most common causes of vision loss have had little hope for treatment. Age-related macular degeneration, or AMD, typically strikes people older than 60 by thinning a layer of cells at the back of the eye known as the retinal pigment epithelium. This layer of cells eliminates waste from the eye and nourishes photoreceptors, the neurons that absorb and convert the light that creates the images we see. As the disease progresses, photoreceptors die, and patients lose central vision—the ability to see what is directly in front of them; peripheral vision is not affected.

Embryonic stem cells may be able to halt the progress of the disease. When researchers used stem cells to create new retinal pigment cells and injected them under the retinas of rats, the new cells helped restore the epithelium, temporarily stopping the degeneration of the retina and rescuing threatened photoreceptors.

This spring scientists will test this method in patients for the first time. The clinical trial, led by biotech company Advanced Cell Technology, will focus on treating the most common form of macular degeneration, known as atrophic (dry) AMD. “There’s a desperate need to be thinking about cell therapies for blinding diseases because not a lot else is coming down the pike,” says Marie Csete, former chief scientific officer at the California Institute for Regenerative Medicine, a research funding agency (she is not involved in the trial).

Some critics warn that patients’ immune systems could reject the foreign cells, and that undifferentiated stem cells could turn into cancer cells. Robert Lanza, chief scientific officer at Advanced Cell Technology, says his team has addressed both concerns. For one, the eye is immune-privileged, meaning it is less likely than other organs to reject foreign tissue; indeed, rejection was not an issue in trials on rats. The company has also developed a test to detect a single undifferentiated stem cell among the retinal pigment cells they will give to patients.

If trials prove the treatment is safe, Lanza will test it on patients with earlier stages of AMD, the better to prevent the onset of the disease. At best, though, the treatment would spare vision but not restore sight that has already been lost.


MIND Reviews: The Moral Lives of Animals

The Moral Lives of Animals
by Dale Peterson. Bloomsbury Press, 2011

In the summer of 2000 scientists saw a young elephant collapse and die on a trail in the African forest. In the following hours, elephants passing by attempted to help and revive her by lifting her dead body off the ground.

In The Moral Lives of Animals, Tufts University lecturer Dale Peterson argues that this kind of behavior provides evidence that humans are not the only animals that developed a sense of morality—other mammals, among them elephants, dolphins and chimpanzees, also have strong impulses for cooperation, kindness and fairness. Peterson, a long-time collaborator of primatologist Jane Goodall, makes the case that the morality of animals, such as humans, requires obeying certain social rules and evolved as a means to mediate conflicts that inevitably arise within communities.

Peterson asserts that animals are capable of exhibiting moral behaviors because these behaviors do not require advanced intellectual capabilities—they only result from strong emotional ­responses: “A bully makes you angry. A cheater leaves you depressed.” Some of Peterson’s stories illustrate animal emotions vividly, such as accounts of elephants committing suicide. Peterson writes that loggers in Myanmar (Burma) capture and train elephants to help with timber extraction. The taming procedure can be so distressing to the animals that some cut off their own air supply by stepping on their trunks.

Peterson also presents evidence that mammals can distinguish right from wrong. For example, a primatologist at a Tanzanian research site once tried to distract a chimp by pretending he had seen something intriguing in the distance. The chimp fell for the deception and went to explore but soon returned and slapped the mischievous primatologist on the head. Peterson interprets the chimp’s reaction as evidence that he recognized the researcher’s deceit as immoral and punished him.

Although the underlying motivations for many of these behaviors are a matter of interpretation, Moral Lives is a thought-provoking read that glimpses into the minds and behaviors of mammals.


30 years After Televised Spat, Rival Anthropologists Agree to Bury the Hand-Ax

Paleoanthropology is a discipline known as much for its feuds as for its findings. Among the best known of these clashes is a longstanding one between two of the field's most famous scientists, Donald Johanson and Richard Leakey. Both have led expeditions that made such extraordinary fossil discoveries as the 3.2-million-year old "Lucy" skeleton from Hadar, Ethiopia (Johanson), and the 1.6-million-year-old "Turkana Boy" skeleton from Turkana, Kenya (Leakey)—and both have done much to popularize human origins. Theirs started off as a friendly rivalry. In a book I wrote with Johanson called Lucy's Legacy (Harmony, 2009), Johanson described it thusly:

"Friendly rivalry is at times a good thing because it motivates us all to work a little harder, a little longer, and take chances we otherwise might not take. Chief among my rivals was Richard Leakey, son of Louis and Mary, who had made some spectacular finds at Lake Turkana in Kenya, including a specimen known as 1470, then considered the earliest evidence of Homo. Tall and lanky with sun-bleached hair and boyish good looks, Richard exuded authority and confidence. We'd met several times, and the previous year I'd brought [a fossil knee from Hadar] to Nairobi so that his team at the National Museums of Kenya could make a cast of it. He graciously allowed me to see their hominid fossil collection, including specimens that hadn't been published yet or even announced. Honored to be a member of the "inner circle" of scholars who were granted such access, I felt it was now my turn to return the favor, so I invited Richard; his wife Meave; and his mother Mary, to Hadar. A licensed pilot, he flew to Ethiopia in his own plane and landed at our hastily cleared airstrip, dubbed Hadar International Airport….As they walked Hadar's astonishingly fossil-rich hillsides, I enjoyed watching their dumbstruck expressions, thinking that was how I must have looked to Maurice [Taeib] when I first came here.

Over dinner we debated the fossil identification of the new hominid jaws that Alemayehu [Asfaw] had found. Richard favored classifying the larger one as part of a member of our own genus, Homo, whereas I thought it belonged to a male australopithecine. We weren't just arguing about the jaws, though. Richard believed that the 1470 skull was 3 million years old. But like many other experts in the field I suspected the geological dating was wrong because the animal remains found along with it, particularly the pigs, were identical to those from the Omo that were dated at about 2 million years. Although we disagreed, I was thrilled to be exchanging ideas with some of the giants in the field….

On Saturday we drove Richard and his group out to the airstrip, helped them load up, and waved good-bye as they took off for the flight back to Kenya. The following day I found Lucy."

Donald Johanson and Richard Leakey -- recent photosThat was 1974. Lucy—and the question of her place in the family tree—intensified this rivalry, because Johanson proposed that Lucy's species, Australopithecus afarensis, was older than and ancestral to our genus, Homo, whereas Leakey argued that Homo had very ancient roots, which would have excluded the then-known australopithecines as ancestors. Their disagreement on this matter culminated in a very public falling-out in 1981 during a recorded debate between the two men at the American Museum of Natural History in New York City that was later broadcast on Cronkite's Universe. Roger Lewin and Virginia Morell have written at length about this drama-filled moment, as have others.

So it's a big deal that Johanson and Leakey met once again at the American Museum of Natural History and shared the stage for the first time in 30 years to discuss human origins and why it matters. CNN chief medical correspondent Sanjay Gupta moderated the discussion on May 5, which started at 6:30 p.m. EDT and was streamed live at:

Top: Johanson via Wikimedia Commons/Marlith (left) and Leakey Flickr/Ed Schipul (right)
Bottom: Johanson (left) and Leakey via Wikimedia Commons/William Campbell/Sygma/Corbis (right)


Scientists show how shifts in temperature prime immune response

Researchers at The Scripps Research Institute have found a temperature-sensing protein within immune cells that, when tripped, allows calcium to pour in and activate an immune response. This process can occur as temperature rises, such as during a fever, or when it falls—such as when immune cells are "called" from the body's warm interior to a site of injury on cooler skin.

The study, recently published online ahead of print by Nature Chemical Biology, is the first to find such a sensor in —specifically, in the T lymphocytes that play a central role in activation of killer immune cells. The , STIM1, previously known as an endoplasmic reticulum (ER) sensor, had been thought to be important in immune function, and now the scientists show it is also a temperature sensor.

"Temperature has a profound effect on all biological processes including immune responses, but surprisingly little is known about molecules in immune cells that sense temperature sifts," said the study's principal investigator, Scripps Research Professor Ardem Patapoutian. "Here we show that STIM1 senses temperature and has a profound impact on immune cells."

This is the second family of thermosensation molecules that the Patapoutian laboratory has uncovered. The team has isolated and characterized three of six members of the transient receptor potential (TRP) family of ion channels—the so-called thermoTRPs. "These proteins translate temperature, which is a physical stimulus, into a chemical signal—ions flowing into cells," said Patapoutian.

"ThermoTRPs mainly function in specialized sensory neurons that relay environmental temperature information to the brain."

In this study, the researchers turned to immune cells to look for temperature sensors. "Immune cells can experience dramatic temperature changes under either normal or pathophysiological conditions," said first author Bailong Xiao, a research associate in the Patapoutian laboratory. "The temperature drops significantly when, say, immune cells move from the 37 degree Celsius temperature of the spleen to skin, where it is normally 33 degrees. During fever, core body temperature can rise to 41 degrees." Scientists have discussed for decades whether is beneficial to the immune system. The researchers believe that identification of a molecular sensor of temperature within immune cells provides a novel avenue to address such questions mechanistically.

The research team, which included Bertrand Coste and Jayanti Mathur, also of the Patapoutian lab, found that STIM1 can be activated by heat with a high degree of temperature sensitivity. Both STIM1 and a plasma membrane pore-forming protein known as Orai1 have recently been identified as essential components of the so-called the calcium release activated calcium (CRAC) channel. But STIM1 had not been known to be heat sensitive until this research, according to Xiao.

The process goes like this: STIM1 proteins are located on the ER, which is the organelle that stores calcium inside the cell. When a sudden change in temperature occurs, STIM1 proteins cluster together and translocate close to the plasma membrane. There, these clusters then can activate Orai1, which leads to the opening of the channel pore and an influx of calcium to activate the cell. Calcium is essential for a number of cellular functions, and, in immune cells, a sustained influx of calcium into these cells activates gene expression and cell proliferation. It turns the immune cell "on," Xiao said.

The function of STIM1 and Orai1 had already been known to be critical to immune function, Xiao said. Mutations in genes encoding either of the proteins lead to development of severe combined immunodeficiency (SCID), the so-called "bubble boy" disease characterized by a complete absence of immunity.

Given the relatively wide expression pattern of STIM1, the researchers suggest that STIM1 may also function as a temperature sensor in other tissues in addition to immune system, including skin, brain, skeletal muscle, and even in blood platelets, all of which could experience moderate but significant temperature changes. For example, temperature-induced STIM1-mediated calcium influx may help muscle cells remodel after exercise, Xiao explained. "We know that calcium is very important for skeletal muscle physiology and remodeling.
Temperature can rise in skeletal muscles when they are exercised."

The same principle may be working in blood platelets, where STIM1 is also found and plays important roles, he said. When platelets move to the skin surface to repair a cut, the change in temperature may activate STIM1, which can contribute to platelet activation, resulting in formation of a clot, Xiao said.

While sensing is essential for survival and efficient metabolism, it is not clear yet if and how these findings can be clinically translated, said Patapoutian. "It is too early to make predictions on the implications of these findings, but STIM1 and Orai1 are of interest to the pharmaceutical industry given their role in immunodeficiency."

More information: Temperature-dependent STIM1 activation induces Ca2+ influx and modulates gene expression, Nature Chemical Biology (2011) doi:10.1038/nchembio.558

Intracellular Ca2+ is essential for diverse cellular functions. Ca2+ entry into many cell types including immune cells is triggered by depleting endoplasmic reticulum (ER) Ca2+, a process termed store-operated Ca2+ entry (SOCE). STIM1 is an ER Ca2+ sensor. Upon Ca2+ store depletion, STIM1 clusters at ER–plasma membrane junctions where it interacts with and gates Ca2+-permeable Orai1 ion channels. Here we show that STIM1 is also activated by temperature. Heating cells caused clustering of STIM1 at temperatures above 35 °C without depleting Ca2+ stores and led to Orai1-mediated Ca2+ influx as a heat off-response (response after cooling). Notably, the functional coupling of STIM1 and Orai1 is prevented at high temperatures, potentially explaining the heat off-response. Additionally, physiologically relevant temperature shifts modulate STIM1-dependent gene expression in Jurkat T cells. Therefore, temperature is an important regulator of STIM1 function.

Provided by The Scripps Research Institute (news : web)

Chemistry curbs spreading of carbon dioxide

The presence of even a simple chemical reaction can delay or prevent the spreading of stored carbon dioxide in underground aquifers, new research from the University of Cambridge has revealed.

The findings may have implications for in saline aquifers – one of the many methods being explored to mitigate rising CO2 levels in the atmosphere.

Depending on the strength of the reaction between dissolved CO2 and porous rock, the new research shows that distinct scenarios of CO2 transport may occur in deep saline rock formations.

Jeanne Andres, a Schlumberger Foundation PhD researcher at the Department of Chemical Engineering and Biotechnology at the University of Cambridge, said: "If one knows the physical properties of the aquifer, one can now calculate the movement of CO2 across it, and when it will begin to mix with the brine. In theory, one can manipulate the strength of reactions, thereby engineering the movement of CO2 – keeping it in one area or moving it to another within the aquifer - to enhance its storage underground."

CO2 fingers. Strong between dissolved and porous rock (top) may stop CO2 fingers from spreading from the top throughout an aquifer's depth, in contrast to systems with no reaction (bottom).

With weak reactions, the CO2 will spread from the top throughout the depth of the aquifer, but with stronger reactions, the CO2 remains near the top of the reservoir, leaving the deeper part inactive.

The strength of these reactions can vary significantly among deep saline reservoirs - rock formations possess a wide range of chemical reaction rates depending on the mineralogy (e.g. calcite, dolomite, etc) as well as other factors such as temperature and pressure,. With the new insight this research provides, it would now be feasible to consider creating and injecting compounds which could alter the strength of reactions in the aquifer.

To arrive at their conclusions, the researchers established that the basic interaction between fluid flow and the rate of chemical reactions (chemical kinetics) in a deep porous medium is governed by a single dimensionless number, which measures the rate of diffusion and reaction compared to that of the natural mixing of fluids (convection).

As applied to the storage of CO2 underground, the scientists demonstrate how this new parameter controls CO2 flow and mixing in briny porous rock. Through numerical simulations, the researchers found that above this parameter's critical value, reaction stabilizes the CO2 system and convection no longer occurs. Below the parameter's critical value, stronger reactions result in longer delays in the onset of convective mixing throughout the reservoir.

For systems with similar convective mixing strengths, stronger reactions, indicated by rising values of the new parameter, can increase the minimum rate at which pure, lighter CO2 dissolves into the brine, enhancing storage and reducing the risk of leakage.

Dr Silvana Cardoso, Reader in the Department and project leader, said: "This research shows how rigorous mathematical analysis coupled with strong physical understanding can help us grasp the complex interactions of flow and reaction in a carbon reservoir. Such knowledge will be valuable in guiding future approaches to carbon storage."

More information: The paper 'Onset of convection in a porous medium in the presence of chemical reaction' was published in the journal Physical Review E, Vol.83, No.4. Authors: J.T.H. Andres and S.S.S. Cardoso , DOI: 10.1103/PhysRevE.83.046312

Provided by University of Cambridge (news : web)