A pioneering study to gauge the toxicity of quantum dots in primates has found the tiny crystals to be safe over a one-year period, a hopeful outcome for doctors and scientists seeking new ways to battle diseases like cancer through nanomedicine. Medical uses for quantum dots -- tiny luminescent crystals -- could include image-guided surgery, light-activated therapies and sensitive diagnostic tests.
The research, which will appear on May 20 in Nature Nanotechnology online, is likely the first to test the safety of quantum dots in primates.
In the study, scientists found that four rhesus monkeys injected with cadmium-selenide quantum dots remained in normal health over 90 days. Blood and biochemical markers stayed in typical ranges, and major organs developed no abnormalities. The animals didn't lose weight.
Two monkeys observed for an additional year also showed no signs of illness.
Quantum dots are tiny luminescent crystals that glow brightly in different colors. Medical researchers are eyeing the crystals for use in image-guided surgery, light-activated therapies and sensitive diagnostic tests. Cadmium selenide quantum dots are among the most studied, with potential applications not only in medicine, but as components of solar cells, quantum computers, light-emitting diodes and more.
The new toxicity study -- completed by the University at Buffalo, the Chinese PLA General Hospital, China's ChangChun University of Science and Technology, and Singapore's Nanyang Technological University -- begins to address the concern of health professionals who worry that quantum dots may be dangerous to humans.
The authors caution, however, that more research is needed to determine the nanocrystals' long-term effects in primates; most of the potentially toxic cadmium from the quantum dots stayed in the liver, spleen and kidneys of the animals studied over the 90-day period.
"This is the first study that uses primates as animal models for in vivo studies with quantum dots," said paper coauthor Paras Prasad, UB professor of chemistry and medicine, and executive director of UB's Institute for Lasers, Photonics and Biophotonics (ILPB). "So far, such toxicity studies have focused only on mice and rats, but humans are very different from mice. More studies using animal models that are closer to humans are necessary."
The cadmium build-up, in particular, is a serious concern that warrants further investigation, said Ken-Tye Yong, a Nanyang Technological University assistant professor who began working with Prasad on the study as a postdoctoral researcher at UB.
Because of that concern, the best in-vivo applications for cadmium-selenide quantum dots in medicine may be the ones that use the crystals in a limited capacity, said Mark Swihart, a third coauthor and a UB professor of chemical and biological engineering. Image-guided surgery, which could involve a single dose of quantum dots to identify a tumor or other target area, falls into this category.
"The Heaven's Lights are fed by the energy generated inside the furnaces of Hell; I AM One Conductive Wire! "
A strong laser beam can remove an electron from an atom -- a process which takes place almost instantly. At the Vienna University of Technology, this phenomenon could now be studied with a time resolution of less than ten attoseconds (ten billionths of a billionth of a second). Scientists succeeded in watching an atom being ionized and a free electron being "born." These measurements yield valuable information about the electrons in the atom, which up until now hasn't been experimentally accessible, such as the time evolution of the electron's quantum phase -- the beat to which the quantum waves oscillate. Wave-like Quantum Interference
In the experiment, short laser pulses are fired at atoms. Each laser pulse can be described as a light wave -- the wave sweeps over the atom, and therefore, the electric field around the atom changes. The electric field rips an electron away from the atom -- but the precise moment at which this happens cannot be defined. "The electron is not removed from the atom at one point in time during the interaction with the laser pulse. There is a superposition of several processes, as it is often the case in quantum mechanics," says Markus Kitzler from the Photonics Institute at TU Vienna. One single electron leaves the atom at different points in time, and these processes combine, much like waves on a water surface, combining to a complex wave pattern.
"These quantum mechanical wave-interferences give us information about the initial quantum state of the electron during the ionization process," says Professor Joachim Burgdörfer (Institute for Theoretical Physics, TU Vienna), whose research team closely collaborated with the experimentalists at the Photonics Institute.
It's All About the Phase
Like waves, quantum particles in this experiment can interfere constructively or destructively. The wave cycle of the electrons is extremely short, the quantum phase changes rapidly. "Usually, this quantum phase can hardly be measured," says Markus Kitzler. Combining high precision measurements and elaborate theoretical calculations, information about the electron's quantum phase can now be obtained.
An important tool for these measurements was a very special laser beam, containing two different wavelengths. The laser pulse interacting with the atom could be tailored very precisely. Using these pulses, the scientists could measure the quantum phase which the electron had inside the atom (with respect to the beat defined by the laser light) before it was removed by the laser. "This quantum phase that we can measure now, also tells us about the electron's energy states inside the atom, and about the precise position at which the ionization took place," says Markus Kitzler. To do that, the scientists had to measure the quantum phase with an incredible precision of less than ten attoseconds.
Ultrashort timescales -- far away from everyday experience
The time span of ten attoseconds (10*10^(-18) seconds) is so short that any comparison to everyday timescales fails. The ratio of ten years to a second is 300 million to one. Dividing a second by the same factor takes us to the incredibly short time scale of three nanoseconds -- in this period, light travels one meter. This is the time scale of microelectronics. Again dividing this tiny period of time by a factor of 300 million, we arrive at about ten attoseconds. This, is the timescale of atomic processes. It is the order of magnitude of an electron's period orbiting the nucleus. In order to measure or to influence these processes, scientists have been striving to access these timescales for years.
"The Heaven's Lights are fed by the energy generated inside the furnaces of Hell; I AM One Conductive Wire! "
New Species Top 10 List: Underworld Worm, Walking Cactus Creature, Blue Tarantula, Sneezing Monkey, and More
ScienceDaily (May 23, 2012) —The International Institute for Species Exploration at Arizona State University and a committee of scientists from around the world announced their picks for the top 10 new species described in 2011. This is the fifth year for the top 10 new species list, which was released May 23 to coincide with the anniversary of the birth of Carolus Linnaeus, the Swedish botanist who was responsible for the modern system of plant and animal names and classifications.
The top 10 new species list was announced May 23 by the International Institute for Species Exploration at Arizona State University. The 2012 list includes a teensy attack wasp, night-blooming orchid, underworld worm, ancient “walking cactus” creature, blue tarantula, Nepalese poppy, giant millipede, sneezing monkey, fungus named for a TV cartoon character and a beautiful but venomous jellyfish. (Credit: Composite by Sara Pennak/International Institute for Species Exploration/Arizona State University)
On this year's top 10 new species list are a sneezing monkey, a beautiful but venomous jellyfish, an underworld worm and a fungus named for a popular TV cartoon character. The top 10 new species also include a night-blooming orchid, an ancient walking cactus creature and a tiny wasp. Rounding out this year's list are a vibrant poppy, a giant millipede and a blue tarantula.
"The top 10 is intended to bring attention to the biodiversity crisis and the unsung species explorers and museums who continue a 250-year tradition of discovering and describing the millions of kinds of plants, animals and microbes with whom we share this planet," said Quentin Wheeler, an entomologist who directs the International Institute for Species Exploration at ASU.
Members of the international committee who made their selection from more than 200 nominations look for "species that capture our attention because they are unusual or because they have traits that are bizarre," said Mary Liz Jameson, an associate professor at Wichita State University who chaired the international selection committee. "Some of the new species have interesting names; some highlight what little we really know about our planet," she said.
Images and other information about the top 10 new species, including the explorers who made the discoveries and recorded them in calendar year 2011, are online at http://species.asu.edu. Also at the site is a Google world map that pinpoints the location for each of the top 10 new species. This year's top 10 come from Brazil, Myanmar, the Dutch Caribbean, South Africa, Papua New Guinea, Spain, Borneo, Nepal, China and Tanzania.
Describing the discoveries
Sneezing monkey:Since 2000, the number of mammals discovered each year averages about 36. So it was nothing to sneeze at when a new primate came to the attention of scientists conducting a gibbon survey in the high mountains of Myanmar (formerly Burma). Rhinopithecus strykeri, named in honor of Jon Stryker, president and founder of the Arcus Foundation, is the first snub-nosed monkey to be reported from Myanmar and is believed to be critically endangered. It is distinctive for its mostly black fur and white beard and for sneezing when it rains.
Bonaire banded box jelly:This strikingly beautiful yet venomous jellyfish looks like a box kite with colorful, long tails. The species name, Tamoya ohboya, was selected by a teacher as part of a citizen science project, assuming that people who are stung exclaim "Oh boy!" A video of the species, which has been spotted near the Dutch Caribbean island of Bonaire,
Devil's worm:Measuring about 0.5 millimeters (1/50 or 0.02 inches) these tiny nematodes are the deepest-living terrestrial multicellular organisms on the planet. They were discovered at a depth of 1.3 kilometers (8/10 mile) in a South African gold mine and given the name Halicephalobus mephisto in reference to the Faust legend of the devil because the new species is found at such a depth in the Earth's crust and has survived immense underground pressure as well as high temperatures (37 degrees Celsius or 98.6 degrees Fahrenheit). According to its discoverers, carbon dating indicated that the borehole water where this species lives had not been in contact with Earth's atmosphere for the last 4,000 to 6,000 years.
Night-blooming orchid:A slender night stalker is one way to describe this rare orchid from Papua New Guinea whose flowers open around 10 at night and close early the next morning. It was described by scientists from the Royal Botanic Gardens, Kew and Leiden University, who named it Bulbophyllum nocturnum from the Latin word meaning "at night." It is believed to be the first night-blooming orchid recorded among the more than 25,000 known species of orchids.
Parasitic wasp:Ants beware! This new species of parasitic wasp cruises at just one centimeter (less than half an inch) above the ground in Madrid, Spain, in search of its target: ants. With a target in sight, the teensy wasp attacks from the air like a tiny dive bomber, depositing an egg in less than 1/20 of a second. A video of the wasp, named Kollasmosoma sentum, dropping an egg on its target.
SpongeBob SquarePants mushroom:Named Spongiforma squarepantsii, after the cartoon character SpongeBob SquarePants, this new fungi species looks more like a sponge than a typical mushroom. One of its characteristics is that its fruiting body can be squeezed like a sponge and bounce back to its normal size and shape. This fungus, which smells fruity, was discovered in forests on the island of Borneo in Malaysia.
Nepalese autumn poppy:This vibrant, tall, yellow poppy found in Nepal may have gone undescribed because of its high mountain habitat (10,827 to 13,780 feet). Named Meconopsis autumnalis for the autumn season when the plant flowers, there is evidence that this species was collected before but not recognized as new until intrepid botanists collecting plants miles from human habitation in heavy monsoon rains made the "rediscovery."
Giant millipede: A giant millipede about the length of a sausage bears the common name "wandering leg sausage," which also is at the root of its Latin name: Crurifarcimen vagans. The species holds a new record as the largest millipede (16 centimeters or about 6.3 inches) found in one of the world's biodiversity hotspots, Tanzania's Eastern Arc Mountains. The new species is about 1.5 centimeter (0.6 inch) in diameter with 56 more or less podous rings, or body segments bearing ambulatory limbs, each with two pairs of legs.
Walking cactus (lobopod fossil):Although this new species looks more like a "walking cactus" than an animal at first glance, Diania cactiformis belongs to an extinct group called the armoured Lobopodia, which had wormlike bodies and multiple pairs of legs. The fossil was discovered in Cambrian deposits about 520 million years old from southwestern China and is remarkable in its segmented legs that may indicate a common ancestry with arthropods, including insects and spiders.
Sazima's tarantula:Breathtakingly beautiful, this iridescent hairy blue tarantula is the first new animal species from Brazil to be named on the top 10 list. Pterinopelma sazimai is not the first or only blue tarantula but truly spectacular and from "island" ecosystems on flattop mountains.
Why a top 10 new species list?"The more species we discover, the more amazing the biosphere proves to be, and the better prepared we are to face whatever environmental challenges lie ahead," said the institute's Wheeler, who also is a professor in ASU's School of Sustainability and its School of Life Sciences.
"It is impossible to do justice to the species discoveries made each year by singling out just 10. Imagine being handed 18,000 newly published books packed with fantastic information and stories and before having the opportunity to read them, being asked to pick the best 10," Wheeler said. "With the help of an international committee of experts we do the best we can by picking those with flashy jackets, surprising titles and unexpected plot lines in an effort to draw attention to the whole lot.
"There are many reasons to discover and describe species, and draw attention to this work. Perhaps most obvious is environmental: Unless we know what species exist to begin with, we are powerless to detect, track or mitigate losses of biodiversity," said Wheeler. "Another is biomimetics, turning to species for clues about new and sustainable ways to meet our needs for survival, materials and designs. There is also an intergenerational ethical imperative for species exploration. Because human population levels and activities are driving extinctions, we owe to humans who follow to explore and document our flora and fauna.
"Each species provides a unique chapter in the history of life and unless we discover them now, we stand to lose an enormous amount of irreplaceable evidence about our own origins and relatives," said Wheeler, who is one of an international group of 39 scientists, scholars and engineers who provided a detailed plan in the March 30 issue of the journal Systematics and Biodiversity to chart 10 million species in less than 50 years, and called it a necessary step to sustain the planet's biodiversity.
Marking the May 23 birth of Linnaeus
The annual top 10 new species announcement commemorates the anniversary of the birth of Carolus Linnaeus, who initiated the modern system of plant and animal names and classifications. The 300th anniversary of his birth on May 23 was celebrated worldwide in 2007.
Since Linnaeus initiated the modern systems for naming plants and animals in the 18th century, nearly 2 million species have been named, described and classified. Scientists estimate there are between 8 million and 100 million species on Earth, though most set the number between 8 million to 12 million.
The list of the top 10 new species is issued annually by ASU's International Institute for Species Exploration as part of its public awareness campaign to shine attention on biodiversity and the field of taxonomy. Previous top 10 lists are online at http://species.asu.edu.
Taxon experts pick top 10
"The top 10 new species is all about exploration and discovery," said committee chair Jameson, "and learning more about our planet. Lewis and Clark's discoveries included the pronghorn antelope, prairie dog and prairie rose -- 250 species altogether. But our job is far from over. We need the help of citizens and scientists alike to meet this grand challenge."
Nominations for this year's top 10 list were invited through the species.asu.edu website and also generated by institute staff and committee members.
"We had well over 200 new species nominated this year, and from those, we picked some fascinating "critters," said Jameson.
"Members on the committee come from many places around the world and from many backgrounds, so we bring our own biases to the process; some of us like photosynthesizers, some like predators, some like ocean dwelling critters," she said.
"Committee members had complete freedom in making their choices and developing their own criteria, from unique attributes or surprising facts about the species to peculiar names," Wheeler noted. "I deeply appreciate the taxon experts who gave their knowledge and time to select this year's top 10. By sharing their passion for exploring the biosphere and discovering species, they spread the recognition and appreciation of the critical roles played by taxonomy, botanical gardens and natural history museums in biodiversity exploration and conservation."
In addition to Jameson, a scarab expert, other members on this year's committee included Philippe Bouchet, a marine life expert at the French National Museum of Natural History; Meg Daly, an expert in sea anemones at the Department of Evolution, Ecology and Organismal Biology, Ohio State University; Peter Kämpfer, who expertise is bacteria, Institut für Angewandte Mikrobiologie, Justus-Liebig-Universität Giessen; Niels Peder Kristensen, an expert in Lepidoptera and basal hexapods at the Natural History Museum of Denmark, Zoologisk Museum, University of Copenhagen; James Macklin, an expert on hawthorns and blackberries at the Agriculture and Agri-food Canada; Ellinor Michel, a mollusk expert at the Department of Zoology, Natural History Museum, London; John Noyes, a chalcidoid wasp expert at the Department of Entomology, Natural History Museum, London; Alan Paton, who is an expert on mints at the International Plant Names Index and Royal Botanic Gardens, Kew, UK; Andrew Polaszek, an expert on Hymenoptera (parasitoid wasps) at the Department of Entomology, Natural History Museum, London; Gideon F. Smith, an expert on succulent plants at the Biosystematics Research and Biodiversity Collections, South African National Biodiversity Institute; Antonio Valdecasas, a water mite expert at the Museo Nacional Ciencias Naturales, Madrid, Spain; and Zhi-Qiang Zhang, a mite expert at the New Zealand Arthropod Collection, Landcare Research.
http://www.sciencedaily.com/releases/20 ... 133051.htm
Robots Will Quickly Recognize and Respond to Human Gestures, With New Algorithms
ScienceDaily (May 24, 2012) —New intelligent algorithms could help robots to quickly recognize and respond to human gestures. Researchers at A*STAR Institute for Infocomm Research in Singapore have created a computer program which recognizes human gestures quickly and accurately, and requires very little training.
New intelligent algorithms could help robots to quickly recognize and respond to human gestures. (Credit: Copyright DIUSGOVUK)
Many works of science fiction have imagined robots that could interact directly with people to provide entertainment, services or even health care. Robotics is now at a stage where some of these ideas can be realized, but it remains difficult to make robots easy to operate.
One option is to train robots to recognize and respond to human gestures. In practice, however, this is difficult because a simple gesture such as waving a hand may appear very different between different people. Designers must develop intelligent computer algorithms that can be 'trained' to identify general patterns of motion and relate them correctly to individual commands.
Now, Rui Yan and co-workers at the A*STAR Institute for Infocomm Research in Singapore have adapted a cognitive memory model called a localist attractor network (LAN) to develop a new system that recognize gestures quickly and accurately, and requires very little training.
"Since many social robots will be operated by non-expert users, it is essential for them to be equipped with natural interfaces for interaction with humans," says Yan. "Gestures are an obvious, natural means of human communication. Our LAN gesture recognition system only requires a small amount of training data, and avoids tedious training processes."
Yan and co-workers tested their software by integrating it with ShapeTape, a special jacket that uses fibre optics and inertial sensors to monitor the bending and twisting of hands and arms. They programmed the ShapeTape to provide data 80 times per second on the three-dimensional orientation of shoulders, elbows and wrists, and applied velocity thresholds to detect when gestures were starting.
In tests, five different users wore the ShapeTape jacket and used it to control a virtual robot through simple arm motions that represented commands such as forward, backwards, faster or slower. The researchers found that 99.15% of gestures were correctly translated by their system. It is also easy to add new commands, by demonstrating a new control gesture just a few times.
The next step in improving the gesture recognition system is to allow humans to control robots without the need to wear any special devices. Yan and co-workers are tackling this problem by replacing the ShapeTape jacket with motion-sensitive cameras.
"Currently we are building a new gesture recognition system by incorporating our method with a Microsoft Kinect camera," says Yan. "We will implement the proposed system on an autonomous robot to test its usability in the context of a realistic service task, such as cleaning!"
http://www.sciencedaily.com/releases/20 ... 134525.htm
Italy doctors save baby with smallest artificial heart
ROME, May 24, 2012 (Reuters) —Italian doctors have saved the life of a 16-month-old boy by implanting the world's smallest artificial heart to keep the infant alive until a donor was found for a transplant.
The doctors at Rome's Bambino Gesu hospital said the operation was carried out last month and made public this week. The baby, whose identity has not been disclosed, was kept alive for 13 days before the transplant and is now doing well.
The baby was suffering from dilated myocardiopathy, a heart muscle disease which normally causes stretched or enlarged fibers of the heart. The disease gradually makes the heart weaker, stopping its ability to pump blood effectively.
"This is a milestone," surgeon Antonio Amodeo told Reuters television, adding that while the device was now used as bridge leading to a transplant, in the future it could be permanent.
Before the implant, the child also had a serious infection around a mechanical pump that had been fitted earlier to support the function of his natural heart.
"From a surgical point of view, this was not really difficult. The only difficulty that we met is that the child was operated on several times before," he said.
The tiny titanium pump weighs only 11 grams and can handle a blood flow of 1.5 liters a minute. An artificial heart for adults weighs 900 grams.
Amodeo said the baby had become family and his team wanted to do everything to help him.
"The patient was in our intensive care unit since one month of age. So he was a mascot for us, he was one of us," the doctor said.
"Every day, every hour, for more than one year he was with us. So when we had a problem we couldn't do anything more than our best," he said.
Doctors said the device, invented by American Doctor Robert Jarvik, had been previously tested only on animals.
The hospital needed special permission from Jarvik and the Italian health ministry before going ahead with the procedure.
(Writing by Philip Pullella; Editing by Jon Hemming)
http://www.newsdaily.com/stories/bre84n ... aly-heart/
Plate Tectonics Cannot Explain Dynamics of Earth and Crust Formation More Than Three Billion Years Ago
ScienceDaily (June 1, 2012) —The current theory of continental drift provides a good model for understanding terrestrial processes through history. However, while plate tectonics is able to successfully shed light on processes up to 3 billion years ago, the theory isn't sufficient in explaining the dynamics of Earth and crust formation before that point and through to the earliest formation of planet, some 4.6 billion years ago. This is the conclusion of Tomas Naæraa of the Nordic Center for Earth Evolution at the Natural History Museum of Denmark, a part of the University of Copenhagen. His new doctoral dissertation has just been published by the journal Nature.
“Plate tectonics theory can be applied to about 3 billion years of the Earth’s history. However, the Earth is older, up to 4.567 billion years old. We can now demonstrate that there has been a significant shift in the Earth’s dynamics. Thus, the Earth, under the first third of its history, developed under conditions other than what can be explained using the plate tectonics model,” explains Tomas Næraa. (Credit: Image courtesy of University of Copenhagen)
"Using radiometric dating, one can observe that Earth's oldest continents were created in geodynamic environments which were markedly different than current environments characterised by plate tectonics. Therefore, plate tectonics as we know it today is not a good model for understanding the processes at play during the earliest episodes of Earths's history, those beyond 3 billion years ago. There was another crust dynamic and crust formation that occurred under other processes," explains Tomas Næraa, who has been a PhD student at the Natural History Museum of Denmark and the Geological Survey of Denmark and Greenland -- GEUS.
Plate tectonics is a theory of continental drift and sea floor spreading. A wide range of phenomena from volcanism, earthquakes and undersea earthquakes (and pursuant tsunamis) to variations in climate and species development on Earth can be explained by the plate tectonics model, globally recognized during the 1960's. Tomas Næraa can now demonstrate that the half-century old model no longer suffices.
"Plate tectonics theory can be applied to about 3 billion years of the Earth's history. However, the Earth is older, up to 4.567 billion years old. We can now demonstrate that there has been a significant shift in the Earth's dynamics. Thus, the Earth, under the first third of its history, developed under conditions other than what can be explained using the plate tectonics model," explains Tomas Næraa. Tomas is currently employed as a project researcher at GEUS.
Central research topic for 30 years
Since 2006, the 40-year-old Tomas Næraa has conducted studies of rocks sourced in the 3.85 billion year-old bedrock of the Nuuk region in West Greenland. Using isotopes of the element hafnium (Hf), he has managed to shed light upon a research topic that has puzzled geologists around the world for 30 years. Næraa's instructor, Professor Minik Rosing of the Natural History Museum of Denmark considers Næraa's dissertation a seminal work:
"We have come to understand the context of the Earth's and continent's origins in an entirely new way. Climate and nutrient cycles which nourish all terrestrial organisms are driven by plate tectonics. So, if the Earth's crust formation was controlled and initiated by other factors, we need to find out what controlled climate and the environments in which life began and evolved 4 billion years ago. This fundamental understanding can be of great significance for the understanding of future climate change," says Minik Rosing, who adds that: "An enormous job waits ahead, and Næraas' dissertation is an epochal step."
A continuation of an earlier Article (Into Africa? Fossils Suggest Earliest Anthropoids Colonized Africa) Linked here: http://www.sciencedaily.com/releases/20 ... 133144.htm
Fossil Discovery: More Evidence for Asia, Not Africa, as the Source of Earliest Anthropoid Primates
ScienceDaily (June 4, 2012) —An international team of researchers has announced the discovery of Afrasia djijidae, a new fossil primate from Myanmar that illuminates a critical step in the evolution of early anthropoids -- the group that includes humans, apes, and monkeys. The 37-million-year-old Afrasia closely resembles another early anthropoid, Afrotarsius libycus, recently discovered at a site of similar age in the Sahara Desert of Libya. The close similarity between Afrasia and Afrotarsius indicates that early anthropoids colonized Africa only shortly before the time when these animals lived. The colonization of Africa by early anthropoids was a pivotal step in primate and human evolution, because it set the stage for the later evolution of more advanced apes and humans there.
The image shows two fossilized upper molars. The molar of Afrasia from Myanmar is to the right. The molar of Afrotarsius from Libya is to the left. The map shows the ancient geography of this part of the globe, approximately 38 million years ago. The 3D model is an artist's reconstruction of Afrotarsius. (Credit: Mark Klingler/Carnegie Museum of Natural History)
The scientific paper describing the discovery appears June 4 in Proceedings of the National Academy of Sciences.
For decades, scientists thought that anthropoid evolution was rooted in Africa. However, more recent fossil discoveries in China, Myanmar, and other Asian countries have rapidly altered scientific opinion about where this group of distant human ancestors first evolved. Afrasia is the latest in a series of fossil discoveries that are overturning the concept of Africa as the starting point for anthropoid primate evolution.
"Not only does Afrasia help seal the case that anthropoids first evolved in Asia, it also tells us when our anthropoid ancestors first made their way to Africa, where they continued to evolve into apes and humans," says Chris Beard, Carnegie Museum of Natural History paleontologist and member of the discovery team that also included researchers from Myanmar, Thailand, and France. Beard is renowned for his extensive work on primate evolution and anthropoid origins. "Afrasia is a game-changer because for the first time it signals when our distant ancestors initially colonized Africa. If this ancient migration had never taken place, we wouldn't be here talking about it."
Timing is everything
Paleontologists have been divided over exactly how and when early Asian anthropoids made their way from Asia to Africa. The trip could not have been easy, because a more extensive version of the modern Mediterranean Sea called the Tethys Sea separated Africa from Eurasia at that time. While the discovery of Afrasia does not solve the exact route early anthropoids followed in reaching Africa, it does suggest that the colonization event occurred relatively recently, only shortly before the first anthropoid fossils are found in the African fossil record.
Myanmar's 37-million-year-old Afrasia is remarkable in that its teeth closely resemble those of Afrotarsius libycus, a North African primate dating to about the same time. The four known teeth of Afrasia were recovered after six years of sifting through tons of sediment near Nyaungpinle in central Myanmar. This locality occurs in the middle Eocene Pondaung Formation, where the same international research team discovered Ganlea megacanina, an influential fossil described in 2009 that helped solidify the presence of early anthropoid primates in Asia.
Details of tooth shape in the Asian Afrasia and the North African Afrotarsius fossils indicate that these animals probably ate insects. The size of their teeth suggests that in life these animals weighed around 3.5 ounces (100 g), roughly the size of a modern tarsier.
Because of the complicated structure of mammalian teeth, paleontologists often use them as fingerprints to reconstruct how extinct species are related to each other and their modern relatives. These similarities provide strong evidence that Afrasia's Asian cousins colonized North Africa only shortly before the appearance of Afrotarsius in the African fossil record. If Asian anthropoids had arrived in North Africa earlier, there would have been time for more differences to evolve between Afrasia and Afrotarsius. The close similarity in age and anatomy shared by the two species makes Afrasia a touchstone in the quest to date the spread of anthropoid primates from Asia to Africa.
"For years we thought the African fossil record was simply bad," says Professor Jean-Jacques Jaeger of the University of Poitiers in France, the team leader and a Carnegie Museum research associate. "The fact that such similar anthropoids lived at the same time in Myanmar and Libya suggests that the gap in early African anthropoid evolution is actually real. Anthropoids didn't arrive in Africa until right before we find their fossils in Libya."
Implications for future research
The search for the origin of early anthropoids -- and, by extension, early human ancestors -- is a focal point of modern paleoanthropology. The discovery of Afrasia shows that one lineage of early anthropoids colonized Africa around 37-38 million years ago, but the diversity of early anthropoids known from the Libyan site that produced Afrotarsius libycus hints that the true picture was more complicated. These other Libyan fossil anthropoids may be the descendants of one or more additional Asian colonists, because they don't appear to be specially related to Afrasia and Afrotarsius. Fossil evidence of evolutionary divergence -- when a species divides to create new lineages -- is critical data for researchers in evolution. The groundbreaking discovery of the relationship between Asia's Afrasia and North Africa's Afrotarsius is an important benchmark for pinpointing the date at which Asian anthropoids colonized Africa.
"Groundbreaking research like this underscores the vitality of modern natural history museums," says Sam Taylor, director of Carnegie Museum of Natural History. "Research like this can only be sustained by the irreplaceable collections, curatorial expertise, and scientific infrastructure that natural history museums provide. At the same time, cutting-edge science like this revitalizes our museum's educational programs and propels its mission."
"Reconstructing events like the colonization of Africa by early anthropoids is a lot like solving a very cold case file," says Beard. "Afrasia may not be the anthropoid who actually committed the act, but it is definitely on our short list of prime suspects."
http://www.sciencedaily.com/releases/20 ... 155705.htm
Vallée-Bélisle and Michnick have developed a new approach to visualize how proteins assemble, which may also significantly aid our understanding of diseases such as Alzheimer’s and Parkinson’s, which are caused by errors in assembly. Here shown are two different assembly stages (purple and red) of the protein ubiquitin and the fluorescent probe used to visualize these stage (tryptophan: see yellow). Print resolution available on request.
Enabling bioengineers to design new molecular machines for nanotechnology applications is one of the possible outcomes of a study by University of Montreal researchers that was published in Nature Structural and Molecular Biology June 10. The scientists have developed a new approach to visualize how proteins assemble, which may also significantly aid our understanding of diseases such as Alzheimer's and Parkinson's, which are caused by errors in assembly. "In order to survive, all creatures, from bacteria to humans, monitor and transform their environments using small protein nanomachines made of thousands of atoms," explained the senior author of the study, Prof. Stephen Michnick of the university's department of biochemistry. "For example, in our sinuses, there are complex receptor proteins that are activated in the presence of different odor molecules. Some of those scents warn us of danger; others tell us that food is nearby." Proteins are made of long linear chains of amino acids, which have evolved over millions of years to self-assemble extremely rapidly - often within thousandths of a split second -- into a working nanomachine. "One of the main challenges for biochemists is to understand how these linear chains assemble into their correct structure given an astronomically large number of other possible forms," Michnick said.
"To understand how a protein goes from a linear chain to a unique assembled structure, we need to capture snapshots of its shape at each stage of assembly said Dr. Alexis Vallée-Bélisle, first author of the study. "The problem is that each step exists for a fleetingly short time and no available technique enables us to obtain precise structural information on these states within such a small time frame. We developed a strategy to monitor protein assembly by integrating fluorescent probes throughout the linear protein chain so that we could detect the structure of each stage of protein assembly, step by step to its final structure."
The protein assembly process is not the end of its journey, as a protein can change, through chemical modifications or with age, to take on different forms and functions. "Understanding how a protein goes from being one thing to becoming another is the first step towards understanding and designing protein nanomachines for biotechnologies such as medical and environmental diagnostic sensors, drug synthesis of delivery," Vallée-Bélisle said.
This research was supported by the Natural Sciences and Engineering Research Council of Canada and Le fond de recherché du Québec, Nature et Technologie. The article, "Visualizing transient protein folding intermediates by tryptophan scanning mutagenesis," published in Nature Structural & Molecular Biology, was coauthored by Alexis Vallée-Bélisle and Stephen W. Michnick of the Département de Biochimie de l'Université de Montréal. The University of Montreal is known officially as Université de Montréal.
"The Heaven's Lights are fed by the energy generated inside the furnaces of Hell; I AM One Conductive Wire! "
ScienceDaily (June 15, 2012) — In a paper recently published in European Physical Journal (EPJ) C, researchers hypothesised the existence of mirror particles to explain the anomalous loss of neutrons observed experimentally. The existence of such mirror matter had been suggested in various scientific contexts some time ago, including the search for suitable dark matter candidates.
Researchers hypothesize the existence of mirror particles to explain the anomalous loss of neutrons observed experimentally. (Credit: © Pix by Marti / Fotolia)
Theoretical physicists Zurab Berezhiani and Fabrizio Nesti from the University of l'Aquila, Italy, reanalysed the experimental data obtained by the research group of Anatoly Serebrov at the Institut Laue-Langevin, France. It showed that the loss rate of very slow free neutrons appeared to depend on the direction and strength of the magnetic field applied. This anomaly could not be explained by known physics.
Berezhiani believes it could be interpreted in the light of a hypothetical parallel world consisting of mirror particles. Each neutron would have the ability to transition into its invisible mirror twin, and back, oscillating from one world to the other. The probability of such a transition happening was predicted to be sensitive to the presence of magnetic fields, and could therefore be detected experimentally.
This neutron-mirror-neutron oscillation could occur within a timescale of a few seconds, according to the paper. The possibility of such a fast disappearance of neutrons -- much faster than the ten-minute long neutron decay -- albeit surprising, could not be excluded by existing experimental and astrophysical limits.
This interpretation is subject to the condition that the earth possesses a mirror magnetic field on the order of 0.1 Gauss. Such a field could be induced by mirror particles floating around in the galaxy as dark matter. Hypothetically, the earth could capture the mirror matter via some feeble interactions between ordinary particles and those from parallel worlds.
http://www.sciencedaily.com/releases/20 ... 104347.htm
In a project led by the Max Planck Institute for Evolutionary Anthropology in Leipzig, an international team of scientists has completed the sequencing and analysis of the genome of the last great ape, the bonobo. Bonobos, which together with chimpanzees are the closest living relatives of humans, are known for their peaceful, playful and sexual behaviour that contrasts with the more aggressive behaviour of chimpanzees. The genome sequence provides insights into the evolutionary relationships between the great apes and may help us to understand the genetic basis of these traits. The genome was sequenced from Ulindi, a female bonobo who lives in the Zoo Leipzig. Genome sequences have also been generated from all other great apes -- chimpanzee, orang-utan and gorilla -- making this the final genome of a great ape to be sequenced and providing insights into their relationships with one another and with humans.
The comparison of the genome sequences of bonobo, chimpanzee, and human show that humans differ by approximately 1.3% from both bonobo and chimpanzee. Chimpanzees and bonobos are more closely related, differing by only 0.4%.
Bonobo and chimpanzee territories in central Africa are close to one another and separated only by the Congo River. It has been hypothesized that the formation of the Congo River separated the ancestors of chimpanzees and bonobos, leading to these distinct apes. Examination of the relationship between bonobos and chimpanzees showed that there appears to have been a clean split and no subsequent interbreeding, which supports this hypothesis.
Despite the fact that on average the genomes of bonobos and chimpanzees are equally distant from human, analysis of the genome sequence of the bonobo revealed that for some particular parts of the genome, humans are closer to bonobos than to chimpanzees, while in other regions the human genome is closer to chimpanzees. Further research will determine whether these regions contribute in any way to the behavioural differences and similarities between humans, chimpanzees, and bonobos.
"The Heaven's Lights are fed by the energy generated inside the furnaces of Hell; I AM One Conductive Wire! "
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