Metamaterial Lens Has Ten Times More Power than Any Current Lens

 

(a)Acentimeter-sized preform is assembled by stacking indium wires surrounded by Zeonex29 (a polymer with low absorption at terahertz frequencies) into a hollow polymethyl methacrylate (PMMA) tube. This is heated and drawn to fiber, forming a tapered transition region where the polymer is viscous and the metal is liquid. The end product is a fiber containing a long continuous array of metal microwires. The fiber can be cut into a large number of smaller length devices. (b) Top-view photograph of the preform cross-section. Scale bar: 10 mm. (c) Photograph and (d) X-ray CT scan of the taper used in this work. Scale bar: 8 mm. (e) × 10 (scale bar: 1 mm) and (f) × 40 (scale bar: 50 μm) magnified microscope image of a metamaterial fiber cross-section. (g) Typical side view of the straight fiber section, showing wire continuity and good uniformity over the length scales considered. Scale bar: 500 μm. Alessandro Tuniz, et all.

Researchers from the University of Sidney have developed a metamaterial lens that has ten times the resolution of any current lens.

A lens with ten times the resolution of any current lens, making it a powerful new tool for the biological sciences has been developed by researchers at the University of Sydney.

“This advance means we can unlock previously inaccessible information on the structure of molecules, their chemical make-up and the presence of certain proteins,” said Alessandro Tuniz, lead author of an article on the lens published in Nature Communications today.

Tuniz, a postdoctoral associate at the University, said, “This opens up an entirely new tool for biological studies. It could allow earlier skin cancer diagnosis, because smaller melanomas can be recognized. For breast cancer, it can also be used to more accurately check that all traces of a tumor have been cut out during surgery.”

The four member research team from the University’s School of Physics, including Alessandro Tuniz, are all authors on the paper. They created the lens using fiber optic manufacturing technology.

The lens is a metamaterial – a material with completely new properties not found in nature.

Making the lens was not a matter of making a better form of the lenses already in existence but of making a lens which uses light waves in a way not previously possible.

“Creating metamaterials is a cutting-edge area of science with a massive range of potential uses from aerospace to solar power, telecommunications to defense,” said researcher Dr Boris Kuhlmey.

“The major challenge is making these materials on a scale that is useful. This is one of the first times a metamaterial with a real world application, quickly able to be realized, has been feasible. Within the next two to three years, new terahertz microscopes that are ten times more powerful than current ones will be possible using our metamaterial.

“We know of only two or three other cases worldwide, including for wireless internet and MRI applications, where metamaterials could also be put into practice in the next couple of years.”

The potential to create a new high power lens, able to see much finer details than using conventional lenses was spotted almost a decade ago. It has taken until now to make the lens on a useful scale, a thousand times smaller than the early experimental models.

“The difficulty was making large quantities of matter structured on a micrometric scale,” said Alessandro Tuniz.

The new lens, made of plastic and metal, uses terahertz waves, electromagnetic waves with frequencies higher than microwaves but lower than infrared radiation and visible light. It operates in a region of the spectrum where very few other optical tools are available and all of them have limitations, in particular in terms of resolution.

“If we think of this in comparison to an X-ray which allows us to see inside objects at a high resolution but with associated danger from radiation, by contrast our metamaterial lens allows us not only to see through some opaque materials, but also to gather information on their chemical composition, and even information on interaction between certain molecules, without the danger of X-rays,” Tuniz said.

This means the lens is perfectly suited to analyzing the delivery of drugs to cells, which is crucial to medical research.

This research was undertaken with the Freiburg Materials Research Center from the University of Freiburg and supported by the Australian Research Council, and the Australian National Fabrication Facility using commonwealth and NSW government funding.

Chandra Discovers Dwarf Galaxy Colliding into NGC 1232

A new composite of X-rays (purple) from Chandra and optical data (blue and white) shows the scene of the collision.

A new study reveals that a giant cloud of superheated gas, which is about 6 million degrees, is likely the result of a collision between a dwarf galaxy and a much larger galaxy called NGC 1232.

Observations with NASA’s Chandra X-ray Observatory have revealed a massive cloud of multimillion-degree gas in a galaxy about 60 million light years from Earth. The hot gas cloud is likely caused by a collision between a dwarf galaxy and a much larger galaxy called NGC 1232. If confirmed, this discovery would mark the first time such a collision has been detected only in X-rays, and could have implications for understanding how galaxies grow through similar collisions.

An image combining X-rays and optical light shows the scene of this collision. The impact between the dwarf galaxy and the spiral galaxy caused a shock wave – akin to a sonic boom on Earth – that generated hot gas with a temperature of about 6 million degrees. Chandra X-ray data, in purple, show the hot gas has a comet-like appearance, caused by the motion of the dwarf galaxy. Optical data from the European Southern Observatory’s Very Large Telescope reveal the spiral galaxy in blue and white. X-ray point sources have been removed from this image to emphasize the diffuse emission.

Near the head of the comet-shaped X-ray emission (mouse over the image for the location) is a region containing several very optically bright stars and enhanced X-ray emission. Star formation may have been triggered by the shock wave, producing bright, massive stars. In that case X-ray emission would be generated by massive star winds and by the remains of supernova explosions as massive stars evolve.

Will we soon be extinct?

 Do you ever walk around with the vague feeling that you're going to die soon? That could be because -- according a recent study -- the Earth might be due for a catastrophic mass extinction.
Population ecologists -- scientists who study the relationship between species and the environment -- from the Universities of York and Leeds in Great Britain took a closer look at the fossil record recently. They found that, historically speaking, we're living in a climate that traditionally has seen the extinction of large numbers of species.
The fossil record is the history of our planet. It's composed of information gathered from fossils, rock layers, ice samples and other geological phenomena. When put together, this information forms a picture of life and climate on Earth over the past 550 million years.
The population ecologists compared 520 million years of Earth's climate change with species extinction throughout the same period. What they found is somewhat alarming. During times of cool weather -- called icehouse periods -- biodiversity thrives. Biodiversity is the presence of a large number of different species. If an ecosystem (or planet) is diverse, then the conditions are right to support evolution, reproduction and genetic divergence. In other words, if our planet was a business, then biodiversity means business is good.
But during warm greenhouse periods, biodiversity suffers. This lack of biodiversity appears to be due to mass extinction -- the loss of large numbers of different species. According to the British population ecologists' study, as the global climate has heated up in the past, large numbers of species have died out.
So why might this be a big deal for us? Some of the worst mass extinctions found in the fossil record took place during climates very similar to the one in which we currently live. The York and Leeds researchers suggest that, based on predicted increases in temperatures over this century, Earth could see another mass extinction event as soon as a few generations from now. That means our younger readers' grandchildren could be around when this mass extinction occurs.
But science can't say for certain that it will. There's no evidence that periods of global warming have been directly responsible for mass extinctions. But researchers are able to show direct correlations between global warming and mass extinctions in the past. Higher temperatures loom conspicuously during these periods of extinction.
The worst mass extinction found in the fossil record took place 251 million years ago, during the Permian Period at the end of the Paleozoic Era. At that time, 95 percent of all of the species on Earth met their demise [source: University of York]. No one can say exactly why this mass extinction took place. Some scientists believe that a series of comets hit the planet and caused the oceans to become acidic (also creating acid rain inland). Others believe that poisonous gas from erupting volcanoes caused the same acidic cataclysm. Either way, it's clear that during this same period the global temperature also rose.
Regardless, why should we humans care if the planet may soon see another mass extinction like the one at the end of the Permian Period? After all, we've beaten acid rain before. And even if it gets hot outside, we have air conditioners. We (and our pets) should be okay, even if a mass extinction occurs -- right? Probably not. Find out on the next page why losing 95 percent of all species is really, really bad for the surviving 5 percent.

How Do Planes Fly: Thrust and Drag

 

Drop a stone into the ocean and it will sink into the deep. Chuck a stone off the side of a mountain and it will plummet as well. Sure, steel ships can float and even very heavy airplanes can fly, but to achieve flight, you have to exploit the four basic aerodynamic forces: lift, weight, thrust and drag. You can think of them as four arms holding the plane in the air, each pushing from a different direction.

First, let's examine thrust and drag. Thrust, whether caused by a propeller or a jet engine, is the aerodynamic force that pushes or pulls the airplane forward through space. The opposing aerodynamic force is drag, or the friction that resists the motion of an object moving through a fluid (or immobile in a moving fluid, as occurs when you fly a kite).

If you stick your hand out of a car window while moving, you'll experience a very simple demonstration of drag at work. The amount of drag that your hand creates depends on a few factors, such as the size of your hand, the speed of the car and the density of the air. If you were to slow down, you would notice that the drag on your hand would decrease.

We see another example of drag reduction when we watch downhill skiers in the Olympics. Whenever they get the chance, they'll squeeze down into a tight crouch. By making themselves "smaller," they decrease the drag they create, which allows them to zip faster down the hill.

A passenger jet always retracts its landing gear after takeoff for a similar reason: to reduce drag. Just like the downhill skier, the pilot wants to make the aircraft as small as possible. The amount of drag produced by the landing gear of a jet is so great that, at cruising speeds, the gear would be ripped right off the plane.

For flight to take place, thrust must be equal to or greater than the drag. If, for any reason, the amount of drag becomes larger than the amount of thrust, the plane will slow down. If the thrust is increased so that it's greater than the drag, the plane will speed up.

On the next page, we'll discuss weight and lift.

MY CONTRY MOROCCO

أول تجربة على البشر لتقنية جديدة لزرع النخاع العظمي

أجرى أطباء في مستشفى "غريت اورموند ستريت" في لندن تجربة لتقنية رائدة في زرع النخاع العظمي.

وكان محمد أحمد، الذي يبلغ من العمر نحو خمس سنوات، من بين أول ثلاثة أطفال في العالم يخضع لتجربة العلاج الجديدة.

يعاني محمد من مرض "العوز المناعي المشترك الحاد"، وينتظر ظهور متبرع يكون لديه أنسجة متماثلة منذ سنوات.
نقل محمد الذي يعيش في ميلتون كينيس إلى مستشفى "غريت اورموند ستريت" عندما كان يبلغ من العمر عاما واحدا.
وبسبب مرض محمد، وهو ضعف الجهاز المناعي، فإنه يكون أكثر عرضة للإصابة بالامراض، وبات زرع النخاع العظمي طريقة العلاج الوحيدة المعروفة لمرضه.
ورغم أن محمدا كان على قائمة الانتظار لزرع النخاع العظمي، فإنه أصيب بشدة بمرض أنفلونزا الخنازير.
وخلال هذه الفترة، قرر أطباؤه أن الأمل الحقيقي الوحيد لمحمد هو خضوعه لعملية زرع نخاع عظمي لأنسجة غير متماثلة وكان والده هو المتبرع.
وافق والد محمد ويدعى جميل على المضي قدما في تجربة هذا العلاج.
وقبل تبرعه، تم تطعيم جميل ضد أنفلونزا الخنازير حتى يتسنى لخلايا النخاع العظمي التعرف على كيفية محاربة العدوى.
وقام أطباء محمد بعد ذلك بتعديل خلايا المناعة التي تم التبرع بها والتي تعرف باسم "خلايا تي" في المعمل لعمل ما يعرف "بمفتاح الأمان".

شبكة أمان

ورفض الأعضاء المزروعة هو أحدى المضاعفات الخطيرة لعمليات زرع النخاع العظمي، خاصة حينما لا يكون تماثل الأنسجة بين المتبرع والمتلقي في حالة ممتازة، وهو أحد أصعب التحديات التي تواجه المرضى وأطبائهم.
عمليات الزرع في الأنسجة غير المتماثلة للأطفال تكون عادة خالية من خلايا تي للوقاية من مرض رفض الأعضاء المزروعة، لكن هذا يسبب مشاكل بشأن العدوى الفيروسية وعودة الليوكيميا.
ويتغلب مفتاح الأمان على هذه العملية حيث يتم زرع عدد وافر من "خلايا تي" ليتم التخلص منها لاحقا في حال ظهور مشاكل.
ولحسن الطالع فإن عملية الزرع أجريت لمحمد بنجاح عام 2011، ولم يحتج الأطباء إلى استخدام تحول الأمان.
ورغم أنه لا يزال على محمد تناول عدد من الأدوية للوقاية من أي عدوى مستقبلية، فإن نظامه المناعي بحالة أفضل حاليا.
وقال جميل والد محمد "انتظرنا حتى يكون هناك تماثل كامل، لكن هذا لم يحدث، لكننا استعنا بالله واتخذنا قرارا بتلقي العلاج".
وأضاف " إن محمدا بصحة جيدة الآن، أحيانا ننسى ما عاناه، إننا فقط ممتنون للغاية".
وأوضح أن محمدا سيحتاج بالرغم من ذلك إلى مراقبة عن كثب وكشف طبي بطريقة منتظمة خلال السنوات المقبلة، لكن حالته مطمئنة.
وقال الدكتور وسيم قاسم مستشار طب مناعة الأطفال في مستشفى "غريت اورموند ستريت" والمشرف على الدراسة إن التوجه الجديد، حسبما هو مؤمل، يجب أن يعني أن الأطفال الذين خضعوا لزراعة غير متماثلة يمكنهم أن يستمتعوا بفرصة النجاح ذاتها مثل أولئك الذين أجريت لهم عملية زرع متماثلة بشكل كامل.
وأضاف "نعتقد بأن محمدا عولج من الاضطراب الذي كان يعاني منه، يجب أن يكون باستطاعته أن يعيش حياة عادية إلى حد كبير الآن".
ونشر تقرير كامل حول علاج محمد والبحث الذي أجراه مستشفى غريت اورموند ستريت وجامعة كينغز كوليدج لندن ومعهد صحة الطفل في دورة "بلوس وان".
وهناك حاليا نحو 1600 شخص في بريطانيا بانتظار إجراء زراعة نخاع عظمي و37 ألفا حول العالم.
وهناك فقط 30 في المئة سيجدون متبرع متماثل من داخل عائلاتهم.
وتتضمن التبرعات جمع الدم من أحد العروق أو سحب نخاع العظم من منطقة الحوض باستخدام إبرة أو محقنة.

L'Antimatière

Sciences : Quand la lumière rencontre la matière

were are this places??

Researchers Lay the Groundwork for Touch-Sensitive Prosthetic Limbs

Researchers are working to create a modular, artificial upper limb that will restore natural motor control and sensation in amputees.

New research at the University of Chicago is laying the groundwork for touch-sensitive prosthetic limbs that one day could convey real-time sensory information to amputees via a direct interface with the brain.

The research, published early online in the Proceedings of the National Academy of Sciences, marks an important step toward new technology that, if implemented successfully, would increase the dexterity and clinical viability of robotic prosthetic limbs.

“To restore sensory motor function of an arm, you not only have to replace the motor signals that the brain sends to the arm to move it around, but you also have to replace the sensory signals that the arm sends back to the brain,” said the study’s senior author, Sliman Bensmaia, PhD, assistant professor in the Department of Organismal Biology and Anatomy at the University of Chicago. “We think the key is to invoke what we know about how the brain of the intact organism processes sensory information, and then try to reproduce these patterns of neural activity through stimulation of the brain.”

Bensmaia’s research is part of Revolutionizing Prosthetics, a multi-year Defense Advanced Research Projects Agency (DARPA) project that seeks to create a modular, artificial upper limb that will restore natural motor control and sensation in amputees. Managed by the Johns Hopkins University Applied Physics Laboratory, the project has brought together an interdisciplinary team of experts from academic institutions, government agencies and private companies.

Bensmaia and his colleagues at the University of Chicago are working specifically on the sensory aspects of these limbs. In a series of experiments with monkeys, whose sensory systems closely resemble those of humans, they identified patterns of neural activity that occur during natural object manipulation and then successfully induced these patterns through artificial means.

The first set of experiments focused on contact location, or sensing where the skin has been touched. The animals were trained to identify several patterns of physical contact with their fingers. Researchers then connected electrodes to areas of the brain corresponding to each finger and replaced physical touches with electrical stimuli delivered to the appropriate areas of the brain. The result: The animals responded the same way to artificial stimulation as they did to physical contact.

Next the researchers focused on the sensation of pressure. In this case, they developed an algorithm to generate the appropriate amount of electrical current to elicit a sensation of pressure. Again, the animals’ response was the same whether the stimuli were felt through their fingers or through artificial means.

Finally, Bensmaia and his colleagues studied the sensation of contact events. When the hand first touches or releases an object, it produces a burst of activity in the brain. Again, the researchers established that these bursts of brain activity can be mimicked through electrical stimulation.

The result of these experiments is a set of instructions that can be incorporated into a robotic prosthetic arm to provide sensory feedback to the brain through a neural interface. Bensmaia believes such feedback will bring these devices closer to being tested in human clinical trials.

“The algorithms to decipher motor signals have come quite a long way, where you can now control arms with seven degrees of freedom. It’s very sophisticated. But I think there’s a strong argument to be made that they will not be clinically viable until the sensory feedback is incorporated,” Bensmaia said. “When it is, the functionality of these limbs will increase substantially.”

The Defense Advanced Research Projects Agency, National Science Foundation and National Institutes of Health funded this study. Additional authors include Gregg Tabot, John Dammann, Joshua Berg and Jessica Boback from the University of Chicago; and Francesco Tenore and R. Jacob Vogelstein from the Johns Hopkins University Applied Physics Laboratory.

presentation

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