Sweat Glands Grown from Newly Identified Stem Cells

To date, few fundamentals have been known about the most common gland in the body, the sweat glands that are essential to controlling body temperature, allowing humans to live in the world’s diverse climates. Now, in a tour de force, researchers at The Rockefeller University and the Howard Hughes Medical Institute have identified, in mice, the stem cell from which sweat glands initially develop as well as stem cells that regenerate adult sweat glands.

In their study, published in Cell, the scientists devised a strategy to purify and molecularly characterize the different kinds of stem cell populations that make up the complex sweat duct and glands of the skin. With this information in hand, they studied how these different populations of stem cells respond to normal tissue homeostasis and to different types of skin injuries, and how the sweat glands differ from their close cousins, the mammary glands.

No sweat. Researchers in Elaine Fuchs's lab identified four different types of paw-skin progenitor cells that are responsible for homeostasis and wound repair. This image shows that the sweat ductal and epidermal progenitors (in red) proliferate and repair an epidermal scratch wound; the sweat gland progenitors (in blue and green) show no signs of proliferation to this type of wound, but instead respond to deep glandular wounds.

“Mammary gland stem cells respond to hormonal induction by greatly expanding glandular tissue to increase milk production,” explains Elaine Fuchs, Rebecca C. Lancefield Professor at Rockefeller and an investigator at the Howard Hughes Medical Institute. “In contrast, during a marathon race, sweat gland stem cells remain largely dormant, and glandular output rather than tissue expansion accounts for the 3 liters of sweat our body needs. These fascinating differences in stem cell activity and tissue production are likely at the root why breast cancers are so frequent, while sweat gland cancers are rare.” Their findings might also help in the future to improve treatments for burn patients and to develop topical treatments for people who sweat too much, or too little.

“For now, the study represents a baby step towards these clinical goals, but a giant leap forward in our understanding of sweat glands,” says the study’s lead author, Catherine P. Lu, a postdoctoral researcher in Fuchs’s Laboratory of Mammalian Cell Biology and Development.

Each human has millions of sweat glands but they have rarely been extensively studied possibly due to the difficulty of gathering enough of the tiny organs to research in a lab, says Lu. The mouse is traditionally used as a model for human sweat gland studies, so in this project, Lu and colleagues laboriously extracted sweat glands from the tiny paw pads of mice  the only place they are found in these and most other mammals.

The research team sought to discover whether the different cells that make up the sweat gland and duct contained stem (progenitor) cells, which can help repair damaged adult glands. “We didn’t know if sweat stem cells exist at all, and if they do, where they are and how they behave,” she says. The last major studies on proliferative potential within sweat glands and sweat ducts were conducted in the early 1950s before modern biomedical techniques were used to understand fundamental bioscience.

Fuchs’ team determined that just before birth, the nascent sweat duct forms as a downgrowth from progenitor cells in the epidermis, the same master cells that at different body sites give rise to mammary glands, hair follicles and many other epithelial appendages. As each duct grows deeper into the skin, a sweat gland emerges from its base.

Lu then led the effort to look for stem cells in the adult sweat gland. The gland is made up of two layers -- an inner layer of luminal cells that produce the sweat and an outer layer of myoepithelial cells that squeeze the duct to discharge the sweat.

Lu devised a strategy to fluorescently tag and sort the different populations of ductal and glandular cells. The Fuchs team then injected each population of purified cells into different body areas of female host recipient mice to see what the cells would do.

Interestingly, when introduced into the mammary fat pads, the sweat gland myoepithelial cells generated fluorescent sweat gland-like structures. “Each fluorescent gland had the proper polarized distribution of myoepithelial and luminal cells, and they also produced sodium potassium channel proteins that are normally expressed in adult sweat glands but not mammary glands,” Lu says.

Intriguingly, when the host mice were put through pregnancy, some of the fluorescent sweat glands began to express milk, while still retaining some sweat gland features as well. Even more surprising was that sweat gland myoepithelial cells produced epidermis when engrafted to the back skin of the mice.

“Taken together, these findings tell us that adult glandular stem cells have certain intrinsic features that enable them to remember who they are in some environments, but adopt new identities in other environments,” Fuchs says. “To test the possible clinical implications of our findings, we would need to determine how long these foreign tissues made by the stem cells will last — unless it is long-term, a short-term “fix” might only be useful as a temporary bandage for regenerative medicine purposes,” Fuchs cautions.

Irrespective of whether the knowledge is yet prime-time for the clinics, the findings can now be used to explore the roots of some genetic disorders that affect sweat glands, as well as ways to potential ways to treat them. “We have just laid down some critical fundamentals of sweat gland and sweat duct biology,” Lu says. “Our study not only illustrates how sweat glands develop and how their cells respond to injury, but also identifies the stem cells within the sweat glands and sweat ducts and begins to explore their potential for making tissues for the first time.”

Read more at Science Daily

Researchers Produce First Complete Computer Model of an Organism

In a breakthrough effort for computational biology, the world's first complete computer model of an organism has been completed, Stanford researchers reported last week in the journal Cell.

A team led by Markus Covert, assistant professor of bioengineering, used data from more than 900 scientific papers to account for every molecular interaction that takes place in the life cycle of Mycoplasma genitalium, the world's smallest free-living bacterium.

By encompassing the entirety of an organism in silico, the paper fulfills a longstanding goal for the field. Not only does the model allow researchers to address questions that aren't practical to examine otherwise, it represents a stepping-stone toward the use of computer-aided design in bioengineering and medicine.

"This achievement demonstrates a transforming approach to answering questions about fundamental biological processes," said James M. Anderson, director of the National Institutes of Health Division of Program Coordination, Planning and Strategic Initiatives. "Comprehensive computer models of entire cells have the potential to advance our understanding of cellular function and, ultimately, to inform new approaches for the diagnosis and treatment of disease."

The research was partially funded by an NIH Director's Pioneer Award from the National Institutes of Health Common Fund.

From information to understanding

Biology over the past two decades has been marked by the rise of high-throughput studies producing enormous troves of cellular information. A lack of experimental data is no longer the primary limiting factor for researchers. Instead, it's how to make sense of what they already know.

Most biological experiments, however, still take a reductionist approach to this vast array of data: knocking out a single gene and seeing what happens.

"Many of the issues we're interested in aren't single-gene problems," said Covert. "They're the complex result of hundreds or thousands of genes interacting."

This situation has resulted in a yawning gap between information and understanding that can only be addressed by "bringing all of that data into one place and seeing how it fits together," according to Stanford bioengineering graduate student and co-first author Jayodita Sanghvi.

Integrative computational models clarify data sets whose sheer size would otherwise place them outside human ken.

"You don't really understand how something works until you can reproduce it yourself," Sanghvi said.

Small is beautiful

Mycoplasma genitalium is a humble parasitic bacterium known mainly for showing up uninvited in human urogenital and respiratory tracts. But the pathogen also has the distinction of containing the smallest genome of any free-living organism -- only 525 genes, as opposed to the 4,288 of E. coli, a more traditional laboratory bacterium.

Despite the difficulty of working with this sexually transmitted parasite, the minimalism of its genome has made it the focus of several recent bioengineering efforts. Notably, these include the J. Craig Venter Institute's 2008 synthesis of the first artificial chromosome.

"The goal hasn't only been to understand M. genitalium better," said co-first author and Stanford biophysics graduate student Jonathan Karr. "It's to understand biology generally."

Even at this small scale, the quantity of data that the Stanford researchers incorporated into the virtual cell's code was enormous. The final model made use of more than 1,900 experimentally determined parameters.

To integrate these disparate data points into a unified machine, the researchers modeled individual biological processes as 28 separate "modules," each governed by its own algorithm. These modules then communicated to each other after every time step, making for a unified whole that closely matched M. genitalium's real-world behavior.

Probing the silicon cell

The purely computational cell opens up procedures that would be difficult to perform in an actual organism, as well as opportunities to reexamine experimental data.

In the paper, the model is used to demonstrate a number of these approaches, including detailed investigations of DNA-binding protein dynamics and the identification of new gene functions.

The program also allowed the researchers to address aspects of cell behavior that emerge from vast numbers of interacting factors.

The researchers had noticed, for instance, that the length of individual stages in the cell cycle varied from cell to cell, while the length of the overall cycle was much more consistent. Consulting the model, the researchers hypothesized that the overall cell cycle's lack of variation was the result of a built-in negative feedback mechanism.

Cells that took longer to begin DNA replication had time to amass a large pool of free nucleotides. The actual replication step, which uses these nucleotides to form new DNA strands, then passed relatively quickly. Cells that went through the initial step quicker, on the other hand, had no nucleotide surplus. Replication ended up slowing to the rate of nucleotide production.

These kinds of findings remain hypotheses until they're confirmed by real-world experiments, but they promise to accelerate the process of scientific inquiry.

"If you use a model to guide your experiments, you're going to discover things faster. We've shown that time and time again," said Covert.

Read more at Science Daily

3-D Tumor Models Improve Drug Discovery Success Rate

Imagine millions of cancer cells organized in thousands of small divots. Hit these cells with drugs and when some cells die, you have a candidate for a cancer drug. But a review published this week in the journal Expert Opinion on Drug Discovery argues that these 2D models in fact offer very little information about a potential drug's effects in the body and may often give researchers misleading results.

"Up until the 1980s animal models were the standard for cancer drug discovery. However, with the increase in the number of compounds available for testing and the advent of high-throughput screening (HTS), the use of animals to discover cancer drugs became too costly and unethical. Consequently, 2D cell culture models have become the mainstay for drug discovery or to explore a drug's mechanism of action," says Dan LaBarbera, PhD, investigator at the University of Colorado Cancer Center and the University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences. LaBarbera is principal investigator of the recent review, on which he collaborated with Skaggs colleagues Brian Reid, PhD, and Byong Hoon Yoo, PhD.

LaBarbera cites the gap between results in 2D cells and effects in tumors themselves as a contributing factor for the declining rate of drugs passing FDA approval. In particular, only 5 percent of investigational new drugs targeting cancer make it through clinical trials, at a cost of about $800 million per drug. When you factor in the inevitable failures at various points in development, each approved drug costs an average $1.5 billion.

To increase the drug success rate, LaBarbera suggests something called the multicellular tumor spheroid (MCTS) model. In these models, instead of 2D monolayers, cancer cells are cultured as 3D spheroids. One of the advantages of the MCTS model is that when spheroids reach a critical diameter, they begin to form an outer proliferating zone, an inner quiescent zone, and a central necrotic core -- more faithfully mimicking the microenvironments of human tumors. Additionally, spheroids can be grown in the presence of compounds that mimic extra cellular matrix -- the environment that surrounds and very much affects the growth and behaviors of human tumors.

Instead of indiscriminately killing cells, modern cancer drugs tend to target cells with very specific genetic mutations that turn on and off very specific growth and survival mechanisms that in turn very frequently depend on everything else going on in and around the cells. Using MCTS models, researchers can ask questions about how a drug will penetrate a tumor's heterogeneous 3D structure and how a drug will interact with the environment surrounding these tiny tumors.

"Though these MCTS models have been around since the 1970s, only recently has technology made it possible to use them in place of 2D models for the high-throughput screening used in drug discovery," LaBarbera says.

Remember those millions of cancer cells organized in independent divots that researchers hit with drugs? We're fairly tied to the technology that reads the results of these divots. But micro-technologies now allow multicellular tumor spheroids to be cultured in place of 2D cell cultures using high-throughput micro-well plates -- we can use the same drug testing machinery on these new models. Likewise, materials science technology now exists to grow cells within semipermeable membranes, helping researchers define the shape of the eventual spheres. And as futuristic as it undoubtedly sounds, magnetic cell levitation can help alleviate the problem of cells sticking to the plastic well surface, which limits spheroid growth.

The recent practicality of high-throughput MCTS screening leads LaBarbera to call today a "renaissance" for the technique.

Of course, this 3D testing is initially more expensive and more challenging. "A lot of researchers try to get cost down to pennies per well -- you can see how screening millions of compounds equals millions of dollars -- but this often leads to a higher cost down the road due to a lower success rate. Yes, it may cost more to do HTS with 3D models, but in the long run it may lead to higher success rates and so decreased costs," LaBarbera says.

LaBarbera suggests that another use of the systems biology approach made possible by 3D models like MCTS is to bridge the gap between high-volume, low-accuracy screens and more involved testing in animal models.

Read more at Science Daily

'Seeds' of Massive Black Holes Found at the Center of the Milky Way Galaxy

Many galaxies contain enormous amounts of molecular gas in small areas near their nuclei. Highly condensed molecular gas is a birthplace of lots of stars. Moreover, it is considered to closely relate to activities of galactic nuclei. Therefore, it is important to investigate the physical state and chemical properties of molecular gas at galaxy centers through observation. To obtain detailed observation data, it is best to survey the center of the Milky Way Galaxy in which our solar system exists.

The research team observed emission lines at wavelengths of 0.87 mm, emitted from carbon monoxide molecules in an area of several degrees that includes the center of the Milky Way Galaxy. The ASTE 10 m telescope in the Atacama Desert (4,800 meters above sea level) of Chile was used for observation. More than 250 hours in total were spent on the prolonged observation from 2005 to 2010.

The research team compared this observation data with data of emission lines at wavelengths of 2.6 mm, emitted from carbon monoxide molecules in the same area, which were obtained using the NRO 45m Telescope (Note: 1). When intensity values of emission lines at different wavelengths, emitted from carbon monoxide molecules, are compared, it is possible to estimate temperature and density of molecular gas. In this way, the research team succeeded in drawing detailed distribution maps of "warm, dense" molecular gas of more than 50 degrees Kelvin and more than 10,000 hydrogen molecules per cubic centimeter at the center of the Milky Way Galaxy for the first time ever.

Oka, the research team leader, said, "The results are astonishing." The "warm, dense" molecular gas in that area is concentrated in four clumps (Sgr A, L=+1.3°, L=-0.4°, L=-1.2°). Moreover, it turns out that these four gas clumps are all moving at a very fast speed of more than 100 km/s. Sgr A, one of the four gas clumps, contains "Sagittarius A*," the nucleus of the Milky Way Galaxy. Oka added, "The remaining three gas clumps are objects we discovered for the very first time. It is thought that 'Sagittarius A*' is the location of a supermassive black hole that is approximately 4 million times the mass of the sun. It can be inferred that the gas clump 'Sgr A' has a disk-shaped structure with radius of 25 light-years and revolves around the supermassive black hole at a very fast speed."

On the other hand, the team found signs of expansion other than rotation in the remaining three gas clumps. This means that the gas clumps, L=+1.3°, L=-0.4°and L=-1.2°, have structures that were formed by supernova explosions that occurred within the gas clumps. The gas clump "L=+1.3°" has the largest amount of expansion energy. Its expanding energy is equivalent to 200 supernova explosions. The age of the gas masses is estimated as approximately 60,000 years old. Therefore, given that the energy source is the supernova explosions, the supernova explosions have continued to occur every 300 years.

The research team used the NRO 45m Telescope again to further examine the molecular gas's distribution, motion and composition to determine whether supernova explosions caused the expansion. "Observation clearly showed that the energy source of L=+1.3° is multiple supernova explosions. We detected multiple expansion structures and molecules attributed to shock waves," Oka said about the excitement when observing it. "Based on the observation of L=+1.3°, it is also natural to think that the expanding gas clumps L=-0.4° and L=-1.2° derived energy from multiple supernova explosions," Oka added.

A supernova explosion is a huge explosion that occurs when a star with more massive than eight to ten times the mass of the sun ends its life. Such a high occurrence of supernova explosions (once per 300 years) indicates that many young, massive stars are concentrated in the gas clumps. In other words, this means that there is a massive "star cluster" in each gas clump. Based on the frequency of the supernova explosions, the team estimated the mass of the star cluster buried in L=+1.3°as more than 100,000 times the mass of the sun, which is equivalent to that of the largest star cluster found in the Milky Way Galaxy.

As just described, the star cluster is huge, but it had not been discovered until now. "The solar system is located at the edge of the Milky Way Galaxy's disk, and is about 30,000 light-years away from the center of the Milky Way Galaxy. The huge amount of gas and dust lying between the solar system and the center of the Milky Way Galaxy prevent not only visible light, but also infrared light, from reaching the Earth. Moreover, innumerable stars in the bulge and disc of the Milky Way Galaxy lie in the line of sight. Therefore, no matter how large the star cluster is, it is very difficult to directly see the star cluster at the center of the Milky Way Galaxy," Oka explained.

"Huge star clusters at the center of the Milky Way Galaxy have an important role related to formation and growth of the Milky Way Galaxy's nucleus," said Oka. According to theoretical calculations, when the density of stars at the center of star clusters increases, the stars are merged together, one after another. Then, it is expected that IMBHs with several hundred times the mass of the sun are formed. Eventually, these IMBHs and star clusters sink into the nucleus of the Milky Way Galaxy. It can be thought that the IMBHs and star clusters are then merged further, and form a massive black hole at the Milky Way Galaxy's nucleus. Alternatively, the IMBHs and star clusters could help expand an existing massive black hole.

It can be thought that the supermassive black hole at "Sagittarius A*," the nucleus of the Milky Way Galaxy, has also been grown up through these processes. In summary, the new discovery is the finding of "cradles" of IMBHs that become "seeds" of the supermassive black hole at the nucleus.

Read more at Science Daily

River Networks On Saturn's Largest Moon, Titan, Point to a Puzzling Geologic History

New findings suggest the surface of Saturn's largest moon may have undergone a recent transformation. For many years, Titan's thick, methane- and nitrogen-rich atmosphere kept astronomers from seeing what lies beneath. Saturn's largest moon appeared through telescopes as a hazy orange orb, in contrast to other heavily cratered moons in the solar system.

In 2004, the Cassini-Huygens spacecraft -- a probe that flies by Titan as it orbits Saturn -- penetrated Titan's haze, providing scientists with their first detailed images of the surface. Radar images revealed an icy terrain carved out over millions of years by rivers of liquid methane, similar to how rivers of water have etched into Earth's rocky continents.

While images of Titan have revealed its present landscape, very little is known about its geologic past. Now researchers at MIT and the University of Tennessee at Knoxville have analyzed images of Titan's river networks and determined that in some regions, rivers have created surprisingly little erosion. The researchers say there are two possible explanations: either erosion on Titan is extremely slow, or some other recent phenomena may have wiped out older riverbeds and landforms.

"It's a surface that should have eroded much more than what we're seeing, if the river networks have been active for a long time," says Taylor Perron, the Cecil and Ida Green Assistant Professor of Geology at MIT. "It raises some very interesting questions about what has been happening on Titan in the last billion years."

A paper detailing the group's findings will appear in the Journal of Geophysical Research-Planets.

What accounts for a low crater count?

Compared to most moons in our solar system, Titan is relatively smooth, with few craters pockmarking its facade. Titan is around four billion years old, about the same age as the rest of the solar system. But judging by the number of craters, one might estimate that its surface is much younger, between 100 million and one billion years old.

What might explain this moon's low crater count? Perron says the answer may be similar to what happens on Earth.

"We don't have many impact craters on Earth," Perron says. "People flock to them because they're so few, and one explanation is that Earth's continents are always eroding or being covered with sediment. That may be the case on Titan, too."

For example, plate tectonics, erupting volcanoes, advancing glaciers and river networks have all reshaped Earth's surface over billions of years. On Titan, similar processes -- tectonic upheaval, icy lava eruptions, erosion and sedimentation by rivers -- may be at work.

But identifying which of these geological phenomena may have modified Titan's surface is a significant challenge. Images generated by the Cassini spacecraft, similar to aerial photos but with much coarser resolution, are flat, depicting terrain from a bird's-eye perspective, with no information about a landform's elevation or depth.

"It's an interesting challenge," Perron says. "It's almost like we were thrown back a few centuries, before there were many topographic maps, and we only had maps showing where the rivers are."

Charting a river's evolution

Perron and MIT graduate student Benjamin Black set out to determine the extent to which river networks may have renewed Titan's surface. The team analyzed images taken from Cassini-Huygens, and mapped 52 prominent river networks from four regions on Titan. The researchers compared the images with a model of river network evolution developed by Perron. This model depicts the evolution of a river over time, given variables such as the strength of the underlying material and the rate of flow through the river channels. As a river erodes slowly through the ice, it transforms from a long, spindly thread into a dense, treelike network of tributaries.

Black compared his measurements of Titan's river networks with the model, and found the moon's rivers most resembled the early stages of a typical terrestrial river's evolution. The observations indicate that rivers in some regions have caused very little erosion, and hence very little modification of Titan's surface.

"They're more on the long and spindly side," Black says. "You do see some full and branching networks, and that's tantalizing, because if we get more data, it will be interesting to know whether there really are regional differences."

Going a step further, Black compared Titan's images with recently renewed landscapes on Earth, including volcanic terrain on the island of Kauai and recently glaciated landscapes in North America. The river networks in those locations are similar in form to those on Titan, suggesting that geologic processes may have reshaped the moon's icy surface in the recent past.

Read more at Science Daily

Stone Age Tools Help to Streamline Modern Manufacturing

Innovative research by the National Physical Laboratory (NPL) and the University of Bradford used laser microscopes to explore how stone tools were used in prehistory, and the process has helped streamline surface measurement techniques for modern manufacturers.

The analysis of stone tools is a key factor in understanding early human life including social organisation and diet. Archaeologists at the University of Bradford hypothesised that reconstructing past activities was the best way to study what each tool was used for. They proposed to measure the surface structures of replica stone tools before and after they were used in different reconstructions on two natural materials -- antler and wood.

NPL conducted surface measurement investigations on the replica tools using a confocal microscope to create a map of surface structure. Richard Leach, who led the work at NPL, said: "We measured the surfaces of each tool using a confocal microscope to create a map of its surface structure. Optical measurements create 3D constructions of each surface recorded without physically contacting the surface."

The measurements taken by NPL on each tool before, during and after wear experiments revealed variations in the surfaces that can be used to predict the use of the tools. The results offered interesting insight into the breadth of future experiments necessary to provide conclusive results on the use of stone tools in prehistory.

These measurements also formed part of a development process for new instruments being used in a wider NPL project to support all aspects of manufacturing: from turbine blades to grinding machines to mobile phone screens.

NPL has produced a range of equipment which allows the manufacturing world to gain a better understanding of surface topography, without using stylus instruments -- which have proved slow for in-process applications. NPL has worked in conjunction with the International Organization for Standardization (ISO) to develop the use of optical systems to conduct areal surface measurements, including instrumentation, calibration artefacts, good practice guides and reference software.

More accurate surface measurements allow manufacturers to revolutionise designs of existing and developing technologies, for example by controlling how the surfaces glide through air, absorb or repel water, or reflect light.

Read more at Science Daily

Understanding Hot Nuclear Matter That Permeated the Early Universe

A review article appearing in the July 20, 2012, issue of the journal Science describes groundbreaking discoveries that have emerged from the Relativistic Heavy Ion Collider (RHIC) at the U.S. Department of Energy's Brookhaven National Laboratory, synergies with the heavy-ion program at the Large Hadron Collider (LHC) in Europe, and the compelling questions that will drive this research forward on both sides of the Atlantic. With details that help enlighten our understanding of the hot nuclear matter that permeated the early universe, the article is a prelude to the latest findings scientists from both facilities will present at the next gathering of physicists dedicated to this research -- Quark Matter 2012, August 12-18 in Washington, D.C.

"Nuclear matter in today's universe hides inside atomic nuclei and neutron stars," begin the authors, Barbara Jacak, a physics professor at Stony Brook University and spokesperson for the PHENIX experiment at RHIC, and Berndt Mueller, a theoretical physicist at Duke University. Collisions between heavy ions at machines like RHIC, running since 2000, and more recently, the LHC, make this hidden realm accessible by recreating the extreme conditions of the early universe on a microscopic scale. The temperatures achieved in these collisions -- more than 4 trillion degrees Celsius, the hottest ever created in a laboratory -- briefly liberate the subatomic quarks and gluons that make up protons and neutrons of ordinary atomic nuclei so scientists can study their properties and interactions.

"Quarks and the gluons that hold them together are the building blocks of all the visible matter that exists in the universe today -- from stars, to planets, to people," Jacak said. "Understanding the evolution of our universe thus requires knowledge of the structure and dynamics of these particles in their purest form, a primordial 'soup' known as quark-gluon plasma (QGP)."

RHIC was the first machine to demonstrate the formation of quark-gluon plasma, and determine its unexpected properties. Instead of an ideal gas of weakly interacting quarks and gluons, the QGP discovered at RHIC behaves like a nearly frictionless liquid. This matter's extremely low viscosity (near the lowest theoretically possible), its ability to stop energetic particle jets in their tracks, and its very rapid attainment of such a high equilibrium temperature all suggest that the fluid's constituents are quite strongly interacting, or coupled.

"Understanding strongly coupled or strongly correlated systems is at the intellectual forefront of multiple subfields of physics," the authors write. The findings at RHIC have unanticipated connections to several of these, including conventional plasmas, superconductors, and even some atoms at the opposite extreme of the temperature scale -- a minute fraction of a degree above absolute zero -- which also behave as a nearly perfect fluid with vanishingly low viscosity when confined within an atomic trap.

Another stunning surprise was that mathematical approaches using methods of string theory and theoretical black holes occupying extra dimensions could be used to describe some of these seemingly unrelated strongly coupled systems, including RHIC's nearly perfect liquid. "Physicists were astounded," the authors note. Although the mathematics is clear and well established, the physical reasons for the relationship are still a deep mystery.

When the LHC began its first heavy ion experiments in 2010 -- at nearly 14 times higher energy than RHIC's -- they largely confirmed RHIC's pioneering findings with evidence of a strongly coupled, low-viscosity liquid, albeit at a temperature about 30 percent higher than at RHIC. With a higher energy range, LHC offers a higher rate of rare particles, such as heavy (charm and bottom) quarks, and high- energy jets that can probe particular properties of the QGP system. RHIC can go to lower energies and collide a wide range of ions from protons, to copper, to gold, to uranium -- and produce asymmetric collisions between two different kinds of ions. This flexibility at RHIC allows scientists to produce QGP under a wide variety of initial conditions, and thereby to distinguish intrinsic QGP properties from the influence of the initial conditions.

"The two facilities are truly complementary," said Mueller, whose work on quantum chromodynamics (QCD), the theory that describes the interactions of quarks and gluons, helps guide experiments and interpret results at both facilities. "Both RHIC and the LHC are essential to advancing our understanding of the subatomic interactions that governed the early universe, and how those gave form to today's matter as they coalesced into more ordinary forms."

An essential part of the experimental and theoretical research path going forward will be a detailed exploration of the nuclear "phase diagram" -- how quark matter evolves over a range of energies, temperatures, and densities. LHC will search the highest range of energies, where the matter produced contains quarks and antiquarks in almost complete balance. But all evidence to date from both colliders suggests that RHIC is in the energy "sweet spot" for exploring the transition from ordinary matter to QGP -- analogous to the way an ordinary substance like water changes phases from ice to liquid water to gas.

Read more at Science Daily

Scientists Connect Seawater Chemistry With Ancient Climate Change and Evolution

Humans get most of the blame for climate change, with little attention paid to the contribution of other natural forces. Now, scientists from the University of Toronto and the University of California Santa Cruz are shedding light on one potential cause of the cooling trend of the past 45 million years that has everything to do with the chemistry of the world's oceans.

"Seawater chemistry is characterized by long phases of stability, which are interrupted by short intervals of rapid change," says Professor Ulrich Wortmann in the Department of Earth Sciences at the University of Toronto, lead author of a study to be published in Science this week. "We've established a new framework that helps us better interpret evolutionary trends and climate change over long periods of time. The study focuses on the past 130 million years, but similar interactions have likely occurred through the past 500 million years."

Wortmann and co-author Adina Paytan of the Institute of Marine Sciences at the University of California Santa Cruz point to the collision between India and Eurasia approximately 50 million years ago as one example of an interval of rapid change. This collision enhanced dissolution of the most extensive belt of water-soluble gypsum on Earth, stretching from Oman to Pakistan, and well into Western India -- remnants of which are well exposed in the Zagros mountains.

The authors suggest that the dissolution or creation of such massive gyspum deposits will change the sulfate content of the ocean, and that this will affect the amount of sulfate aerosols in the atmosphere and thus climate. "We propose that times of high sulfate concentrations in ocean water correlate with global cooling, just as times of low concentration correspond with greenhouse periods," says Paytan.

"When India and Eurasia collided, it caused dissolution of ancient salt deposits which resulted in drastic changes in seawater chemistry," Paytan continues. "This may have led to the demise of the Eocene epoch -- the warmest period of the modern-day Cenozoic era -- and the transition from a greenhouse to icehouse climate, culminating in the beginning of the rapid expansion of the Antarctic ice sheet."

The researchers combined data of past seawater sulfur composition, assembled by Paytan in 2004, with Wortmann's recent discovery of the strong link between marine sulfate concentrations and carbon and phosphorus cycling. They were able to explain the seawater sulfate isotope record as a result of massive changes to the accumulation and weathering of gyspum -- the mineral form of hydrated calcium sulfate.

Read more at Science Daily

The Bizarre, Breathtaking Science Photos of Fritz Goro

If science seeks to uncover the truth, then photography seeks to lay that truth bare to the world.

Photographer Fritz Goro understood this sentiment well. His photographs highlight the beautiful, strange, amusing and poignant within the realm of scientific inquiry. Goro spent four decades as a photographer for LIFE magazine and Scientific American. The photos here are a selection of those featured at LIFE.com.

Goro was born in Bremen, Germany, and trained in the Bauhaus school of sculpture and design. He began a career in photojournalism, and by age 30 had become editor of the weekly Munich Illustrated. He left Germany with his wife in 1933 when Hitler came to power, came to the U.S. in 1936, and soon began freelancing for LIFE.

Scientific subjects were his passion, and according to LIFE he said he took photos of things that “more knowledgeable photographers might have considered unphotographable… I began to take pictures of things I barely understood, using techniques I’d never used before.”

Among his subjects were gestating fetuses, blood circulation in the heart, and the separation of plutonium and uranium isotopes to make the atomic bomb. His New York Times obituary hails him as the inventor of macrophotography, and quotes Gerard Piel, former science editor at LIFE, as saying, ”It was (Goro’s) artistry and ingenuity that made photographs of abstractions, of the big ideas from the genetic code to plate tectonics.” Goro also developed techniques for photographing bioluminescence, holograms and lasers.

Read more and see more pictures at Wired Science

World's Oldest Known Bra Found

A 15th century bra was recently unearthed during reconstruction work at a medieval castle. The remarkably modern looking bra is arguably now the world's oldest known brassiere.

Fiber samples taken from the linen bra date to the medieval era, so this item appears to be legit. It pushes back the known history of the modern-styled bra by possibly more than 400 years.

The bra was discovered in a waste-filled vault at Lengberg Castle, East Tyrol, Austria. The stash included more than 2,700 individual textile fragments -- parts of nicely tailored trousers, buttoned shirts, and 4 modern-looking bras.

Beatrix Nutz, an archeologist from the University of Innsbruck, found all of it.

The bra is known as a "longline bra," meanging that the cups are each made from two pieces of linen sewn together vertically.

A press release from the University of Innsbruck further describes the bra as follows:

    The surrounding fabric of somewhat coarser linen extends down to the bottom of the ribcage with a row of six eyelets on the left side of the body for fastening with a lace. The corresponding row of eyelets is missing. Needle-lace is sewn onto the cups and the fabric above thus decorating the cleavage. In the triangular area between the two cups there might have been additional decoration, maybe another sprang-work.

Women, sometimes at the urging of men, have been trying to cover, restrain, or elevate their breasts for ages, with corsets becoming popular in the 16th century. But before the Austrian medieval bra find, there was nothing to indicate the existence of bras with clearly visible cups before the 19th century.

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