miércoles, 29 de enero de 2014

Flexible, transparent conductor created: Discovery brings bendable cell phone, foldable flat-screen TV closer to reality

Researchers have developed a new stretchable and transparent electrical conductor, bringing the potential for a fully foldable cell phone or a flat-screen television that can be folded and carried under your arm closer to reality.


Zhifeng Ren, a physicist at the University of Houston and principal investigator at the Texas Center for Superconductivity, said there long has been research on portable electronics that could be rolled up or otherwise easily transported. But a material that is transparent and has both the necessary flexibility and conductivity has proved elusive -- some materials have two of the components, but until now, finding one with all three has remained difficult.
The gold nanomesh electrodes produced by Ren and his research associates Chuan Fei Guo and Tianyi Sun at UH, along with two colleagues at Harvard University, provide good electrical conductivity as well as transparency and flexibility, the researchers report in a paper published online Tuesday in Nature Communications.
The material also has potential applications for biomedical devices, said Ren, lead author on the paper. The researchers reported that gold nanomesh electrodes, produced by the novel grain boundary lithography, increase resistance only slightly, even at a strain of 160 percent, or after 1,000 cycles at a strain of 50 percent. The nanomesh, a network of fully interconnected gold nanowires, has good electrical conductivity and transparency, and has "ultrahigh stretchability," according to the paper.
And unlike silver or copper, gold nanomesh does not easily oxidize, which Ren said causes a sharp drop in electrical conductivity in silver and copper nanowires. Guo said the group is the first to create a material that is transparent, stretchable and conductive, as well as the first to use grain boundary lithography in the quest to do so. More importantly, he said, it is the first to offer a clear mechanism to produce ultrahigh stretchability.
The grain boundary lithography involved a bilayer lift-off metallization process, which included an indium oxide mask layer and a silicon oxide sacrificial layer and offers good control over the dimensions of the mesh structure.
"This is very useful to the field of foldable electronics," Guo said. "It is much more transportable." Sun noted that Korean electronics maker Samsung demonstrated a cellphone with a bendable screen in October; LG Electronics has introduced a curved cellphone that is available now in Asia.
But neither is truly foldable or stretchable, instead curving slightly to better fit against the user's face. "For that kind of device, we need something flexible, transparent," Sun said of a foldable phone. "If we want to further that technology, we need something else, and the something else could be the technology we are developing."
Ren noted that, although gold nanomesh is superior to other materials tested, even it broke and electrical resistance increased when it was stretched. But he said conductivity resumed when it was returned to the original dimensions.
That didn't prove true with silver, he said, presumably because of high oxidation. The work at the University of Houston was funded by the Department of Energy, while that at Harvard was funded by a National Science Foundation grant.

Even for those who care about technology and want the new tech items as they are launched out, science has always the answer!!!

martes, 28 de enero de 2014

Graphene-like material made of boron a possibility, experiments suggest

Graphene, a sheet of carbon one atom thick, may soon have a new nanomaterial partner. In the lab and on supercomputers, chemists have determined that a cluster of 36 boron atoms forms a flat disc with a hexagonal hole in the middle. The shape fits theoretical predictions for a potential new nanomaterial: "borophene."


Researchers from Brown University have shown experimentally that a boron-based competitor to graphene is a very real possibility. Graphene has been heralded as a wonder material. Made of a single layer of carbon atoms in a honeycomb arrangement, graphene is stronger pound-for-pound than steel and conducts electricity better than copper. Since the discovery of graphene, scientists have wondered if boron, carbon's neighbor on the periodic table, could also be arranged in single-atom sheets. Theoretical work suggested it was possible, but the atoms would need to be in a very particular arrangement.

Boron has one fewer electron than carbon and as a result can't form the honeycomb lattice that makes up graphene. For boron to form a single-atom layer, theorists suggested that the atoms must be arranged in a triangular lattice with hexagonal vacancies -- holes -- in the lattice.
"That was the prediction," said Lai-Sheng Wang, professor of chemistry at Brown, "but nobody had made anything to show that's the case."

"We haven't made borophene yet, but this work suggests that this structure is more than just a calculation."Wang and his research group, which has studied boron chemistry for many years, have now produced the first experimental evidence that such a structure is possible. In a paper published on January 20 in Nature Communications, Wang and his team showed that a cluster made of 36 boron atoms (B36) forms a symmetrical, one-atom thick disc with a perfect hexagonal hole in the middle. "It's beautiful," Wang said. "It has exact hexagonal symmetry with the hexagonal hole we were looking for. The hole is of real significance here. It suggests that this theoretical calculation about a boron planar structure might be right."
It may be possible, Wang said, to use B36 basis to form an extended planar boron sheet. In other words, B36 may well be the embryo of a new nanomaterial that Wang and his team have dubbed "borophene." "We still only have one unit," Wang said. "We haven't made borophene yet, but this work suggests that this structure is more than just a calculation."

The work required a combination of laboratory experiments and computational modeling. In the lab, Wang and his student, Wei-Li Li, probe the properties of boron clusters using a technique called photoelectron spectroscopy. They start by zapping chunks of bulk boron with a laser to create vapor of boron atoms. A jet of helium then freezes the vapor into tiny clusters of atoms. Those clusters are then zapped with a second laser, which knocks an electron out of the cluster and sends it flying down a long tube that Wang calls his "electron racetrack." The speed at which the electron flies down the racetrack is used to determine the cluster's electron binding energy spectrum -- a readout of how tightly the cluster holds its electrons. That spectrum serves as fingerprint of the cluster's structure.

Wang's experiments showed that the B36 cluster was something special. It had an extremely low electron binding energy compared to other boron clusters. The shape of the cluster's binding spectrum also suggested that it was a symmetrical structure.
To find out exactly what that structure might look like, Wang turned to Zachary Piazza, one of his graduate students specializing in computational chemistry. Piazza began modeling potential structures for B36 on a supercomputer, investigating more than 3,000 possible arrangements of those 36 atoms. Among the arrangements that would be stable was the planar disc with the hexagonal hole.

"As soon as I saw that hexagonal hole," Wang said, "I told Zach, 'We have to investigate that.'"
To ensure that they have truly found the most stable arrangement of the 36 boron atoms, they enlisted the help of Jun Li, who is a professor of chemistry at Tsinghua University in Beijing and a former senior research scientist at Pacific Northwest National Laboratory (PNNL) in Richland, Wash. Li, a longtime collaborator of Wang's, has developed a new method of finding stable structures of clusters, which would be suitable for the job at hand. Piazza spent the summer of 2013 at PNNL working with Li and his students on the B36 project. They used the supercomputer at PNNL to examine more possible arrangements of the 36 boron atoms and compute their electron binding spectra. They found that the planar disc with a hexagonal hole matched very closely with the spectrum measured in the lab experiments, indicating that the structure Piazza found initially on the computer was indeed the structure of B36.
That structure also fits the theoretical requirements for making borophene, which is an extremely interesting prospect, Wang said. The boron-boron bond is very strong, nearly as strong as the carbon-carbon bond. So borophene should be very strong. Its electrical properties may be even more interesting. Borophene is predicted to be fully metallic, whereas graphene is a semi-metal. That means borophene might end up being a better conductor than graphene. "That is," Wang cautions, "if anyone can make it."

So here there is another amazing chemical discovery!!! Ther never end of science!!!

viernes, 24 de enero de 2014

Carbon Dioxide Paves the Way to Unique Nanomaterials

In common perception, carbon dioxide is just a greenhouse gas, one of the major environmental problems of humankind. For Warsaw chemists CO2 became, however, something else: a key element of reactions allowing for creation of nanomaterials with unprecedented properties.

That Science is advancing day after day or even second after second is a fact. As you may know, I am a chemist but I cannot even avoid wondering myself when seeing this amazing and fast development of science. This discovery is quite important as it may let people think little by little that chemistry is not that bad.


(Credit: Image courtesy of Institute of Physical Chemistry of the Polish Academy of Sciences)

In reaction with carbon dioxide, appropriately designed chemicals allowed researchers from the Institute of Physical Chemistry of the Polish Academy of Sciences (IPC PAS) in Warsaw and the Faculty of Chemistry, Warsaw University of Technology, (WUT) for production of unprecedented nanomaterials. These novel materials are highly porous, and in their class they show the most extended, and so the largest surface area, which is of key importance for the envisaged use. Prospective applications include storage of energetically important gases, catalysis or sensing devices. Moreover, microporous fluorescent materials obtained using CO2 emit light with quantum yield significantly higher than those of classical materials used in OLEDs.

"Our research is not confined to fabrication of materials. Its particular importance comes from the fact that it opens a new synthetic route to metal carbonate and metal oxide based nanomaterials, the route where carbon dioxide plays a key role," notices Prof. Janusz Lewiński (IPC PAS, WUT).

The papers reporting accomplishments of Prof. Lewiński's group, achieved in cooperation with Cambridge University and University of Nottingham, were published, i.a., by the chemical journals Angewandte Chemie and Chemical Communications.

Carbon dioxide (CO2) is a natural component of Earth's atmosphere. It is the most abundant carbon-based building block, and is involved in the synthesis of glucose, an energy carrier and building unit of paramount importance for living organisms."Carbon dioxide has been for years used in industrial synthesis of polymers. On the other hand, there has been very few research papers reporting fabrication of inorganic functional materials using CO2," says Kamil Sokołowski, a doctoral student in IPC PAS.

Prof. Lewiński's group has shown that appropriately designed precursor compounds in reaction with carbon dioxide lead to fabrication of a microporous material (with pore diameters below 2 nm) resulting from self-assembly of luminescent nanoclusters. Novel microporous material, composed of building blocks with zinc carbonate core encapsulated in appropriately designed organic shell (hydroxyquinoline ligands), is highly luminescent, with photoluminescence quantum yield significantly higher than those of classical fluorescent compounds used in state-of-the-art OLEDs.

"Using carbon dioxide as a building block we were able to construct a highly porous and really highly luminescent material. Can it be used for construction of luminescent diodes or sensing devices? The discovery is new, the research work on the novel material is in progress, but we are deeply convinced that the answer is: yes," says Sokołowski. Polish and international patent applications were filed for the invention and the implementation work in cooperation with a joint venture company is in progress.

The design of precursors was inspired by nature, in particular by the binding of carbon dioxide in enzymatic systems of carbonic anhydrase, an enzyme responsible for fast metabolism of CO2 in human body. Effective enzyme activity is based on its active centre, where a hydroxyzinc (ZnOH) type reaction system is located. The strategy for materials synthesis using carbon dioxide and appropriate alkylhydroxyzinc precursors, seems to be a versatile tool for production of various functional materials. Depending on the composition of the reagents and the process conditions, a mesoporous material (with pore diameter from 2 to 50 nm) composed of zinc carbonate nanoparticles or multinuclear zinc nanocapsules for prospective applications in supramolecular chemistry can be obtained in addition to the material described above.

Further research of Prof. Lewiński's group has shown that the mesoporous materials based on ZnCO3-nanoparticles can be transformed into zinc oxide (ZnO) aerogels. Mesoporous materials made of ZnO nanoparticles with extended surface can be used as catalytic fillings, allowing for and accelerating reactions of various gaseous reagents. Other potential applications are related to semiconducting properties of zinc oxide. That's why the novel materials can be used in future in photovoltaic cells or as a major component of semiconductor sensing devices.

Science development is a never end way. Think about that and have a nice and scientific weekend!!!


miércoles, 22 de enero de 2014

Humans Can Use Smell to Detect Levels of Dietary Fat

New research from the Monell Center reveals humans can use the sense of smell to detect dietary fat in food. As food smell almost always is detected before taste, the findings identify one of the first sensory qualities that signals whether a food contains fat. Innovative methods using odor to make low-fat foods more palatable could someday aid public health efforts to reduce dietary fat intake.

"The human sense of smell is far better at guiding us through our everyday lives than we give it credit for," said senior author Johan Lundström, PhD, a cognitive neuroscientist at Monell. "That we have the ability to detect and discriminate minute differences in the fat content of our food suggests that this ability must have had considerable evolutionary importance."
As the most calorically dense nutrient, fat has been a desired energy source across much of human evolution. As such, it would have been advantageous to be able to detect sources of fat in food, just as sweet taste is thought to signal a source of carbohydrate energy.
Although scientists know that humans use sensory cues to detect fat, it still remains unclear which sensory systems contribute to this ability. The Monell researchers reasoned that fat detection via smell would have the advantage of identifying food sources from a distance.
While previous research had determined that humans could use the sense of smell to detect high levels of pure fat in the form of fatty acids, it was not known whether it was possible to detect fat in a more realistic setting, such as food.
In the current study, reported in the open access journal PLOS ONE, the researchers asked whether people could detect and differentiate the amount of fat in a commonly consumed food product, milk.
To do this, they asked healthy subjects to smell milk containing an amount of fat that might be encountered in a typical milk product: either 0.125, 1.4 or 2.7 %.
The milk samples were presented to blindfolded subjects in three vials. Two of the vials contained milk with the same percent of fat, while the third contained milk with a different fat concentration. The subjects' task was to smell the three vials and identify which of the samples was different.
The same experiment was conducted three times using different sets of subjects. The first used healthy normal-weight people from the Philadelphia area. The second experiment repeated the first study in a different cultural setting, the Wageningen area of the Netherlands. The third study, also conducted in Philadelphia, examined olfactory fat detection both in normal-weight and overweight subjects.
In all three experiments, participants could use the sense of smell to discriminate different levels of fat in the milk. This ability did not differ in the two cultures tested, even though people in the Netherlands on average consume more milk on a daily basis than do Americans. There also was no relation between weight status and the ability to discriminate fat.
"We now need to identify the odor molecules that allow people to detect and differentiate differentiate levels of fat. Fat molecules typically are not airborne, meaning that they are unlikely to be sensed by sniffing food samples," said lead author Sanne Boesveldt, PhD, a sensory neuroscientist. "We will need sophisticated chemical analyses to sniff out the signal."
This study reveals an important applicsation of chemistry that may contribute to improve the live expectancy if we are able to make healthy food more appealing.

lunes, 20 de enero de 2014

Thinking hard weighs heavy on the brain

Balance measures tiny changes in force due to blood flow behind thoughts

When the mind is at work, the brain literally gets heavier. That fact may be surprising, but it isn’t new: In the late 1880s, Italian scientist Angelo Mosso built an intricate full-body balance and reported that mental activity tips the scales. Now, a modern-day version of Mosso’s “human circulation balance” backs him up. Compared with a brain at rest, a brain listening to music and watching a video is indeed heavier, David Field and Laura Inman of the University of Reading in England January 9 report in Brain.

While teaching a course about brain-imaging techniques, Field grew curious whether Mosso’s general approach would work. So he and some students decided to find out. “It was a bit of a mad idea, to be honest,” Field says.
At the heart of both balances lies a simple seesaw lever. As weight shifts in a body, presumably from blood moving, the lever tilts the head or the feet downward, Mosso observed. Field and Inman’s contraption doesn’t actually tip. The researchers put a sensitive scale under the head end, which would register changes in force.
After lots of troubleshooting, which involved eliminating signals created by bodily processes that move blood such as breathing and heart beats, Field and Ingram were able to test mental tasks. Fourteen participants were asked to lie still on the lever, and listen to music or listen to music and simultaneously watch a video of colorful geometric shapes. The part of the brain that detects sound is relatively small, Field says, so the audio plus video test was used to activate a wider swath of the brain and increase the chances of a measurable blood shift.
Right after a two-second blip of either audio or audio and video, blood leaves the brain, as measured by a drop in force, Field and Inman found. This quick dip in blood volume, a phenomenon that’s also seen in functional MRI, may represent the brain preparing for work by shunting waste-ridden blood out via the jugular vein. Seconds after that, a surge of new blood enters the brain, increasing the force measured by the scale.

These changes in force were very small — about 0.005 newtons — and most prominent in the people who both listened to music and watched a video, Field says. It’s hard to calculate how much blood rushes into the brain with each mental task. To know that value, scientists would need to know the distance of the head from the lever’s fulcrum, which could be easily measured, and exactly where the blood came from, which is nearly impossible to know.  
In his original experiments, Mosso found that tasks that required more mental energy made the brain heavier. Reading a page from a mathematics manual seemed to tip the balance more than reading a page from a newspaper. Strong emotions also tipped the scales: When a subject read a letter from an angry creditor, Mosso wrote, “the balance fell at once.”

Until recently, Mosso’s scientific manuscripts had not been described in detail. But Stefano Sandrone of King’s College London unearthed Mosso’s papers in archives and published a description in Brain in 2013.
“We have been neglecting Mosso and his work for so many years. It’s good that someone has begun to find interest in the papers that he wrote,” Sandrone says of the modern-day experiment. He and his colleagues are working on an exhibition of Mosso’s original balance.

Many neuroscientists use functional MRI to detect changes in blood flow in the brain. Usually, fMRI spots regional differences, as when a little blood moves from one part of the brain to another. In contrast, the balance describes overall changes in brain workload, Field says.

The balance is not going to replace modern neuroimaging as a way to see what happens inside the brain. But with refinements, it might ultimately prove to be useful, Sandrone says. “The more measures we have, the more we can approximate the complexity of the brain.” 

Europe's financial support to 20 scientific projects

Europe supports scientific projects of 20 Spanish high-level researchers

Those who consider themselves scientists need some proof of their scientific careers. Therefore, they must publish their results and communicate their foundings. However no science can be made without founding. Having financial support for a purposed scientific project is the key to develope it. Indeed, it is the key fot industrial development. We scientists must do research and try to solve, in a nearer or further future, society's demands. 

Good news are that Europe is going to support some of the best-considered spanish scientific projects. More concretely, 20 Spanish scientists would be given the well-known European Reserach Council (ERC) grant. Their investigations involve hot topics such as new treatments for neurodegenerative illnesses and cancer, new methods and interactions in the mathematical singularity theory and the collateral macroeconomy.

Spain has rise up untill the sixth position as a receiver of these grants -with six more grants than the last call-, then comes United kingdom, Germany, France, The Netherlands, Switzerland and finally Italy.

ERC is going to support an amount of 312 projects of well-considered European scientists with 575 millions of euros. Each of these grants give 1.84 millions of euros as an average and they can rise up to 2.7 millions of euros each.

This organisation claimed that in this last call, they selected a wide range of topics that start from the exploration of the black matter effects and the black energy in the gravitational theory in the use of a geochemical watch to predict volcanic eruptions, and finish with the study of the role of the genetic and environmental factors in the brain connexions of the embryos.

All these topics are of high importance to society. However there are still a few if we want to develop this country and fight agains ignorance. More scientific projects should be supported. There is a huge need of doing research. It is the key of success. 



viernes, 3 de enero de 2014

May you be addicted to your smartphone?

Six disorders have been discovered due to the use of smartphones

The unavoidable need of using the mobile evrytime and everywhere highlights the existent addiction to it. Phil Reed, which is a phycology professor in the Swansea University, reported that the addiction to smartphones can provoque depression and social isolation. Time after time we become more dependent on technology. However, these technologic items can produce different addictions or illnesses. Some of the most known disorders are the following:

1. Nomophobia: is the fear that a person feels when leaving the mobile away. It provoques a feeling of anxiety. One of tis symptoms is the impossibility of being without your phone.

2. Cybersickness: it is a secondary effect of the excessive use of the mobile apps. In this occasion the person feels tired and has a strong headache.

3. iPosture: many mobile users tend to bend theirselves when using the phone. This can cause a huge pressure in the spine and also provoque headache and pain in neck and shoulders.

4. Phantom vibration syndrome: it is a symptom due to the dependence on the mobile. The user thinks that it is vibrating although it is not doing so, or even if it is swithced off. 

5. Dry eye syndrome: the high levels of concentration that a person dedicates to his/her mobile reduces in one third the number of eye blinkings causing eye problems.

6. Finger pain: the massive use of the phone can cause cramps in the fingers, wrists and forearms.

Technology can be really helpful and, indeed, it is. However you have to be aware and make an intelligent use of it. You must keep in mind that a mobile phone is just a thing, just a tool and that you cannot let it take the control of your life and your health.