Posts belonging to Category light

Polymer Nanoparticle Locates And Treats Breast Tumors

One major problem in treating cancer is identifying the location of small tumors and treating them before they metastasize.

In an effort to overcome that problem, researchers at Wake Forest Baptist Medical Center have developed a fluorescing nanoparticle capable of finding tumors, lighting up upon arrival and being activated with light to generate heat to destroy the cancer cells.

A study in which these nanoparticlesHybrid Donor-Acceptor Polymer Particles, or H-DAPPs – successfully located and killed breast cancer skills in mice is published in the current issue of the journal ACS Applied Materials and Interfaces.

An unexpected result was how efficiently the nanoparticles localized to the tumors without any targeting agent,” said the study’s lead author, Nicole Levi-Polyachenko, Ph.D., associate professor of plastic and reconstructive surgery at Wake Forest School of Medicine, part of Wake Forest Baptist. “Achieving high enough levels of H-DAPPs within the tumor to allow it to be seen provides an advantage for knowing exactly where light should be applied to generate heat and kill the cancer cells.

Other investigators have developed nanoparticles to detect tumors or carry drugs, and Levi-Polyachenko’s team has created polymers that strongly absorb infrared light and generate heat. Regarding the new nanoparticle, she said, “It was exciting to figure out the step for combining a heat-generating polymer with a light-emitting polymer to allow for detection and on-demand heat treatment.

H-DAPPs are made of electrically conductive polymers and are smaller than 100 nanometers (0.00000393701 of an inch) in diameter. Their small size and soft composition makes it easy for them to travel through the bloodstream to the tumor.

There is much more research needed to ensure that H-DAPPs can safely be used in humans,” Levi-Polyachenko said. “But we are enthusiastic about exploring the use of H-DAPPs with other cancer types and eventually in patients.


Hydrogen Economy Closer

Washington State University (WSU) researchers have found a way to more efficiently generate hydrogen from water — an important key to making clean energy more viable. Using inexpensive nickel and iron, the researchers developed a very simple, five-minute method to create large amounts of a high-quality catalyst required for the chemical reaction to split water.

Energy conversion and storage is a key to the clean energy economy. Because solar and wind sources produce power only intermittently, there is a critical need for ways to store and save the electricity they create. One of the most promising ideas for storing renewable energy is to use the excess electricity generated from renewables to split water into oxygen and hydrogen. Hydrogen has myriad uses in industry and could be used to power hydrogen fuel-cell carsIndustries have not widely used the water splitting process, however, because of the prohibitive cost of the precious metal catalysts that are required – usually platinum or ruthenium. Many of the methods to split water also require too much energy, or the required catalyst materials break down too quickly.

In their work, the researchers, led by professor Yuehe Lin in the School of Mechanical and Materials Engineering, used two abundantly available and cheap metals to create a porous nanofoam that worked better than most catalysts that currently are used, including those made from the precious metals. The catalyst they created looks like a tiny sponge. With its unique atomic structure and many exposed surfaces throughout the material, the nanofoam can catalyze the important reaction with less energy than other catalysts. The catalyst showed very little loss in activity in a 12-hour stability test.

We took a very simple approach that could be used easily in large-scale production,” said Shaofang Fu, a WSU Ph.D. student who synthesized the catalyst and did most of the activity testing. “The advanced materials characterization facility at the national laboratories provided the deep understanding of the composition and structures of the catalysts,” comments Junhua Song, another WSU Ph.D. student who worked on the catalyst characterization.

The findings are described in the journal Nano Energy.


Artificial Synapse For “Brain-on-a-Chip”

When it comes to processing power, the human brain just can’t be beat. Packed within the squishy, football-sized organ are somewhere around 100 billion neurons. At any given moment, a single neuron can relay instructions to thousands of other neurons via synapses — the spaces between neurons, across which neurotransmitters are exchanged. There are more than 100 trillion synapses that mediate neuron signaling in the brain, strengthening some connections while pruning others, in a process that enables the brain to recognize patterns, remember facts, and carry out other learning tasks, at lightning speeds.

Researchers in the emerging field of “neuromorphic computing” have attempted to design computer chips that work like the human brain. Instead of carrying out computations based on binary, on/off signaling, like digital chips do today, the elements of a “brain on a chip” would work in an analog fashion, exchanging a gradient of signals, or “weights,” much like neurons that activate in various ways depending on the type and number of ions that flow across a synapse.

In this way, small neuromorphic chips could, like the brain, efficiently process millions of streams of parallel computations that are currently only possible with large banks of supercomputers. But one significant hangup on the way to such portable artificial intelligence has been the neural synapse, which has been particularly tricky to reproduce in hardware.

Now engineers at MIT have designed an artificial synapse in such a way that they can precisely control the strength of an electric current flowing across it, similar to the way ions flow between neurons. The team has built a small chip with artificial synapses, made from silicon germanium. In simulations, the researchers found that the chip and its synapses could be used to recognize samples of handwriting, with 95 percent accuracy.

The design, published today in the journal Nature Materials, is a major step toward building portable, low-power neuromorphic chips for use in pattern recognition and other learning tasks.


Solar-driven Hydrogen Economy

Hydrogen as a fuel source, rather than hydrocarbons like oil and coal, offers many benefits. Burning hydrogen produces harmless water with the potential to eliminate carbon dioxide emissions and their environmental burden. In pursuit of technologies that could lead to a breakthrough in achieving a hydrogen economy, a key issue is making hydrogen cheaply. Using catalysts to split water is the ideal way to generate hydrogen, but doing so usually requires an energy input from other chemicals, electricity, or a portion of sunlight which has high enough energy.

Now researchers at Osaka University have developed a new catalytic system for efficiently splitting water and making hydrogen with energy from normal sunlight. Their study was recently reported in Angewandte Chemie International Edition.

It has not been possible to use visible light for photocatalysis, but our approach of combining nanostructured black phosphorus for water reduction to hydrogen and bismuth vanadate for water oxidation to oxygen lets us make use of a wide range of the solar spectrum to make hydrogen and oxygen with unprecedented efficiency,” lead author Mingshan Zhu says.

Black phosphorus has a flat, two-dimensional structure similar to that of graphene and strongly absorbs light across the whole of the visible spectrum. The researchers combined the black phosphorus with bismuth vanadate, which is a well-known water oxidation catalyst.

In the same way that plants shuttle electrons between different structures in natural photosynthesis to split water and make oxygen, the two components of this new catalyst could rapidly transfer electrons excited by sunlight. The amounts of the two components was also optimized in the catalyst, leading to production of hydrogen and oxygen gases in an ideal 2:1 ratio.


Flat Lens Boost Virtual Reality

Metalensesflat surfaces that use nanostructures to focus light — promise to revolutionize optics by replacing the bulky, curved lenses currently used in optical devices with a simple, flat surface.  But, these metalenses have remained limited in the spectrum of light they can focus well Now a team of researchers at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) has developed the first single lens that can focus the entire visible spectrum of light — including white light — in the same spot and in high resolution. This has only ever been achieved in conventional lenses by stacking multiple lenses.

Focusing the entire visible spectrum and white light – combination of all the colors of the spectrum — is so challenging because each wavelength moves through materials at different speeds. Red wavelengths, for example, will move through glass faster than the blue, so the two colors will reach the same location at different times resulting in different foci. This creates image distortions known as chromatic aberrations.

Cameras and optical instruments use multiple curved lenses of different thicknesses and materials to correct these aberrations, which, of course, adds to the bulk of the device.

Metalenses have advantages over traditional lenses,” says Federico Capasso, Professor of Applied Physics at SEAS and senior author of the research. “Metalenses are thin, easy to fabricate and cost effective. This breakthrough extends those advantages across the whole visible range of light. This is the next big step. Using our achromatic lens, we are able to perform high quality, white light imaging. This brings us one step closer to the goal of incorporating them into common optical devices such as cameras“.

The research is published in Nature Nanotechnology.


Fabric Made Of Nanofibers With Embedded OLED

In South Korea, Professor Kyung Cheol Choi from the School of Electrical Engineering (KAIST)  and his team succeeded in fabricating highly efficient Organic Light-Emitting Diodes (OLEDs) on an ultra-thin fiber. The team expects the technology, which produces high-efficiency, long-lasting OLEDs, can be widely utilized in wearable displays. Existing fiber-based wearable displays’ OLEDs show much lower performance compared to those fabricated on planar substrates. This low performance caused a limitation for applying it to actual wearable displays.

In order to solve this problem, the team designed a structure of OLEDs compatible to fiber and used a dip-coating method in a three-dimensional structure of fibers. Through this method, the team successfully developed efficient OLEDs that are designed to last a lifetime and are still equivalent to those on planar substrates.
The team identified that solution process planar OLEDs can be applied to fibers without any reduction in performance through the technology. This fiber OLEDs exhibited luminance and current efficiency values of over 10,000 cd/m^2(candela/square meter) and 11 cd/A (candela/ampere).
The team also verified that the fiber OLEDs withstood tensile strains of up to 4.3% while retaining more than 90% of their current efficiency. In addition, they could be woven into textiles and knitted clothes without causing any problems.Moreover, the technology allows for fabricating OLEDs on fibers with diameters ranging from 300㎛ down to 90㎛, thinner than a human hair, which attests to the scalability of the proposed fabrication scheme.
Noting that every process is carried out at a low temperature (~105℃), fibers vulnerable to high temperatures can also employ this fabrication scheme.
Professor Choi said, “Existing fiber-based wearable displays had limitations for applicability due to their low performance. However, this technology can fabricate OLEDs with high performance on fibers. This simple, low-cost process opens a way to commercialize fiber-based wearable displays.”

In 2025 Humanity Could Benefit From A Major New Source Of Clean Power

An international project to generate energy from nuclear fusion has reached a key milestone, with half of the infrastructure required now built. Bernard Bigot, the director-general of the International Thermonuclear Experimental Reactor (Iter), the main facility of which is based in southern France, said the completion of half of the project meant the effort was back on track, after a series of difficulties. This would mean that power could be produced from the experimental site from 2025.

Nuclear fusion occurs when two atoms combine to form a new atom and a neutron. The atoms are fired into a plasma where extreme temperatures overcome their repulsion and forces them together. The fusion releases about four times the energy produced when an atom is split in conventional nuclear fission

The effort to bring nuclear fusion power closer to operation is backed by some of the world’s biggest developed and emerging economies, including the EU, the US, China, India, Japan, Korea and Russia. However, a review of the long-running project in 2013 found problems with its running and organisation. This led to the appointment of Bigot, and a reorganisation that subsequent reviews have broadly endorsed.

Fusion power is one of the most sought-after technological goals in the pursuit of clean energy. Nuclear fusion is the natural phenomenon that powers the sun, converting hydrogen into helium atoms through a process that occurs at extreme temperatures.

Replicating that process on earth at sufficient scale could unleash more energy than is likely to be needed by humanity, but the problem is creating the extreme conditions necessary for such reactions to occur, harnessing the resulting energy in a useful way, and controlling the reactions once they have been induced.

The Iter project aims to use hydrogen fusion, controlled by large superconducting magnets, to produce massive heat energy which would drive turbines – in a similar way to the coal-fired and gas-fired power stations of today – that would produce electricity. This would produce power free from carbon emissions, and potentially at low cost, if the technology can be made to work at a large scale.

For instance, according to Iter scientists, an amount of hydrogen the size of a pineapple could be used to produce as much energy as 10,000 tonnes of coal.


How To Store Solar Energy In A Non-Electric Battery

Materials chemists have been trying for years to make a new type of battery that can store solar or other light-sourced energy in chemical bonds rather than electrons, one that will release the energy on demand as heat instead of electricity–addressing the need for long-term, stable, efficient storage of solar power.

Now a group of materials chemists at the University of Massachusetts Amherst led by Dhandapani Venkataraman, with Ph.D. student and first author Seung Pyo Jeong, Ph.D. students Larry Renna, Connor Boyle and others, report that they have solved one of the major hurdles in the field by developing a polymer-based system. It can yield energy storage density – the amount of energy stored – more than two times higher than previous polymer systems. Details appear in the current issue of Scientific Reports.

Venkataraman and Boyle say that previous high energy storage density achieved in a polymeric system was in the range of 200 Joules per gram, while their new system is able to reach an average of 510 Joules per gram, with a maximum of 690. Venkataraman says, “Theory says that we should be able to achieve 800 Joules per gram, but nobody could do it. This paper reports that we’ve reached one of the highest energy densities stored per gram in a polymeric system, and how we did it.”


Glass Blocks Generate Electricity Using Solar Energy

Buildings consume more than forty percent of global electricity and reportedly cause at least a third of carbon emissions. Scientists want to cut this drastically – and create a net-zero energy future for new buildings. Build Solar want to help. The firm has created a glass brick containing small solar cells.


On top of this we have placed in some intelligent optics which are able to focus the incoming sunlight onto these solar cells almost throughout the day. When we do that we are able to generate a higher amount of electrical output from each solar cell that we are using,” says Dr Hasan Baig, founder of Build Solar.
As well as converting the sun’s power to electricity, the bricks have other abilities.
The product is aligned to provide three different things, including electricity, daylighting, and thermal insulation which is generally required by any kind of construction product. More importantly it is aesthetic in its look, so it fits in very well within the building architecture,” adds Dr Baig.
Using Building Integrated Photovoltaics, the technology would be used in addition to existing solar roof panels. The University of Exeter spin-off is fine-tuning the design, which works in many colours. The company says the product could be market ready by the end of next year.


New Quantum Computer Uses 10,000 Times Less Power

Japan has unveiled its first quantum computer prototype, amid a global race to build ever-more powerful machines with faster speeds and larger brute force that are key towards realising the full potential of artificial intelligence. Japan’s machine can theoretically make complex calculations 100 times faster than even a conventional supercomputer, but use just 1 kilowatt of power – about what is required by a large microwave oven – for every 10,000 kilowatts consumed by a supercomputer. Launched recently, the creators – the National Institute of Informatics, telecom giant NTT and the University of Tokyo – said they are building a cloud system to house their “quantum neural network” technology.

In a bid to spur further innovation, this will be made available for free to the public and fellow researchers for trials at
The creators, who aim to commercialise their system by March 2020, touted its vast potential to help ease massive urban traffic congestion, connect tens of thousands of smartphones to different base stations for optimal use in a crowded area, and even develop innovative new drugs by finding the right combination of chemical compounds.

Quantum computers differ from conventional supercomputers in that they rely on theoretical particle physics and run on subatomic particles such as electrons in sub-zero temperatures. Most quantum computers, for this reason, destabilise easily and are error-prone, thereby limiting their functions.

We will seek to further improve the prototype so that the quantum computer can tackle problems with near-infinite combinations that are difficult to solve, even by modern computers at high speed,” said Stanford University Professor Emeritus Yoshihisa Yamamoto, who is heading the project.
Japan’s prototype taps into a 1km-long optical fibre cable packed with photons, and exploits the properties of light to make super-quick calculations. Its researchers said they deemed the prototype ready for public use, after tests showed that it was capable of operating stably around the clock at room temperature.


Breathing in Delhi air equivalent to smoking 44 cigarettes a day

It was early on the morning when residents in the Indian capital of Delhi first began to notice the thick white haze that had descended across the city. Initially viewed as a mild irritant, by mid-week its debilitating effects were evident to all, as the city struggled to adapt to the new eerie, martian-like conditions brought about by the pollution.

The World Health Organization considers anything above 25 to be unsafe. That measure is based on the concentration of fine particulate matter, or PM2.5, per cubic meter. The microscopic particles, which are smaller than 2.5 micrometers in diameter, are considered particularly harmful because they are small enough to lodge deep into the lungs and pass into other organs, causing serious health risks.
With visibility severely reduced, trains have been canceled, planes delayed and cars have piled into each other, with multiple traffic accidents reported across the city. On the afternoon, city chiefs closed all public and private schools, requesting instead that the city’s tens of thousands of school-aged children remain indoors; they banned incoming trucks and halted civil construction projects; while they announced new plans to begin implementing a partial ban on private car use as of next week. But as the city woke up to a fourth straight day of heavy pollution, practical considerations were being overtaken by more serious concerns, with journalists and doctors warning residents of the long-term health implications.

Air quality readings in the Indian capital have reached frightening levels in recent days, at one point topping the 1,000 mark on the US embassy air quality index. Across the capital, doctors reported a surge in patients complaining of chest pain, breathlessness and burning eyes. “The number of patients have increased obviously,” said Deepak Rosha, a pulmonologist at Apollo Hospital, one of the largest private hospitals in Delhi. “I don’t think it’s ever been so bad in Delhi. I’m very angry that we’ve had to come to this.”
Breathing in air with a PM2.5 content of between 950 to 1,000 is considered roughly equivalent to smoking 44 cigarettes a day, according to the independent Berkeley Earth science research group.

Photovoltaics: Light Absorption Enhanced by Up to 200 Percent

Sunlight reflected by solar cells is lost as unused energy. The wings of the butterfly Pachliopta aristolochiae are drilled by nanostructures (nanoholes) that help absorbing light over a wide spectrum far better than smooth surfaces. Researchers of Karlsruhe Institute of Technology (KIT) in Germany, have now succeeded in transferring these nanostructures to solar cells and, thus, enhancing their light absorption rate by up to 200 percent.

 “The butterfly studied by us is very dark black. This signifies that it perfectly absorbs sunlight for optimum heat management. Even more fascinating than its appearance are the mechanisms that help reaching the high absorption. The optimization potential when transferring these structures to photovoltaics (PV) systems was found to be much higher than expected,” says Dr. Hendrik Hölscher of KIT’s Institute of Microstructure Technology (IMT).


The scientists of the team of Hendrik Hölscher and Radwanul H. Siddique (formerly KIT, now Caltech) reproduced the butterfly’s nanostructures in the silicon absorbing layer of a thin-film solar cell. Subsequent analysis of light absorption yielded promising results: Compared to a smooth surface, the absorption rate of perpendicular incident light increases by 97% and rises continuously until it reaches 207% at an angle of incidence of 50 degrees. “This is particularly interesting under European conditions. Frequently, we have diffuse light that hardly falls on solar cells at a vertical angle,” Hendrik Hölscher says. However, this does not automatically imply that efficiency of the complete PV system is enhanced by the same factor, says Guillaume Gomard of IMT. “Also other components play a role. Hence, the 200 percent are to be considered a theoretical limit for efficiency enhancement.

The scientists have reported their results in the journal Science Advances. (DOI: 10.1126/sciadv.1700232.)