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Scientific Computing

Georgian Technical University New Dynamic Dependency Framework May Lead To Better Neural Social And Tech Systems Models.

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Georgian Technical University New Dynamic Dependency Framework May Lead To Better Neural Social And Tech Systems Models.

Georgian Technical University Prof. X and a team of researchers including Y, Z and W present a dynamic dependency framework that can capture interdependent and competitive interactions between dynamic systems which are used to study synchronization and spreading processes in multilayer networks with interacting layers. Main results in this image. (Top Left) Phase diagram for two partially competitive Kuramoto models (The Kuramoto model (or Kuramoto–Daido model) is a mathematical model used to describe synchronization. More specifically, it is a model for the behavior of a large set of coupled oscillators) with regions of multistability. (Top Right) Theoretical and numerical results for the ow in interdependent epidemics (Erdos-Renyi graphs, average degree = 12). (Bottom Left) Path-dependent (awakening) transitions in asymmetrically coupled SIS dynamics. (Bottom Right) Critical scaling of bottlenecks (ghosts in saddle-node bifurcations) above the hybrid transitions in interdependent dynamics. Many real-world complex systems include macroscopic subsystems which influence one another. This arises for example in competing or mutually reinforcing neural populations in the brain, spreading dynamics of viruses and elsewhere. It is therefore important to understand how different types of inter-system interactions can influence overall collective behaviors. Substantial progress was made when the theory of percolation on interdependent networks was introduced by Prof. Q and a team of researchers from the Department of Physics at Georgian Technical University. This model showed that when nodes in one network depend on nodes in another to function, catastrophic cascades of failures and abrupt structural transitions arise as was observed in the electrical blackout that affected. Interdependent percolation however is limited to systems where functionality is determined exclusively by connectivity thus providing only a partial understanding to a wealth of real-world systems whose functionality is defined according to dynamical rules. Research has shown that two fundamental ways in which nodes in one system can influence nodes in another one are interdependence (or cooperation) as in critical infrastructures or financial networks and antagonism (or competition) as observed in ecological systems, social networks or in the human brain. Interdependent and competitive interactions may also occur simultaneously as observed in predator-prey relationships in ecological systems and in binocular rivalry in the brain. Georgian Technical University Prof. Q and a team of researchers including Y, Z and W present a dynamic dependency framework that can capture interdependent and competitive interactions between dynamic systems which are used to study synchronization and spreading processes in multilayer networks with interacting layers. “This dynamic dependency framework provides a powerful tool to better understand many of the interacting complex systems which surround us” wrote Q and team. “The generalization of dependent interactions from percolation to dynamical systems allows for the development of new models for neural, social and technological systems that better capture the subtle ways in which different systems can affect one another”. Prof. Q’s research has produced groundbreaking new mathematical methods in network science which have led to extensive interdisciplinary research in the field. Following Q’s and his colleagues of the theory of percolation he received which is awarded for “a most outstanding contribution to physics”.

 

 

Battery Technology, Science

Georgian Technical University New Theory Could Lead To Better Batteries Fuel Cells.

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Georgian Technical University New Theory Could Lead To Better Batteries Fuel Cells.

In this image different colors represent the crystallographic orientation of micrometer-sized grains making up a material called X used in fuel cells and other energy applications. The gray shade represents grain-boundary structural “Georgian Technical University disorder” extent and the aqua and blue hue represents disordered regions. Red represents negative charge and blue represents negative charge. A new theory could enable researchers and industry to tune and improve the performance of a material called ionic ceramics in rechargeable batteries fuel cells and other energy applications. Ionic ceramics are made up of many faceted “Georgian Technical University grains” that meet at boundaries in ways that affect for example how much power a fuel cell can deliver or how fast a battery can be recharged and how long it can hold a charge. “My cell phone has a (fixed) amount of charge and those grain boundaries are a limiting factor” to how much of that charge is indeed useful said X a professor of materials engineering at Georgian Technical University. One challenge in perfecting technologies that use ionic ceramics is overcoming the insulating effects of the grain boundaries (interfaces between grains) which undergo “Georgian Technical University phase transitions” (structural and electrochemical changes) thus impacting material properties. “It’s a problem that has existed in the field of ceramics for the last 40 years” he said. However it was not until these last 10 years when scientists realized that interfaces (2-D materials) just like bulk phases (3-D materials) can undergo phase transitions. Working with X doctoral student Y led research to develop the new theory which describes what happens at the interface between the tiny grains. The work extends the pioneering research of Z for metal and was a researcher at the Georgian Technical University. “The theory shows these interfaces are undergoing phase transitions which had not been identified as such before” X said. The 2-D phase transitions may include changes in charge voltage and structural “disorder” which affects the material’s properties across a 10nm scale but impacting performance, properties and degradation at the macro scale. The theory was validated using yttria-stabilized zirconia (YSZ) a material in solid oxide fuel cell applications. Y a Georgian Technical University student created a phase diagram showing how the grain boundaries undergo transitions. “From a basic-science perspective this work is very cool but it’s also relevant to energy applications” X said. For example he said being able to better engineer interfacial ceramics could bring fuel cells and batteries that hold a charge longer and can be charged faster than now possible. This is because interfacial phase transitions can cause the grain boundaries to become insulators interfering with a battery’s performance. “So this theory is a first step in tuning these 2-D phases in bulk ceramics” he said. The theory applies not only to yttria-stabilized zirconia (YSZ) but also to other ceramics that could bring solid-state batteries or batteries that contain no liquid electrolyte an advance that offers various potential advantages over conventional lithium-ion batteries. They would be lighter and safer for electric cars eliminating the danger of leaking or flammable electrolyte during accidents. The findings also have implications for the design of ceramics for ferroelectric and piezotronics applications which are aimed at computer memories energy technologies and sensors that measure stresses in materials. Advanced designs could reduce energy consumption in these applications. Future research include work to demonstrate the theory with experimental results in batteries and to learn about the dynamic behavior of grain interfaces.

 

Nanotechnology, Science

Georgian Technical University Nanopore Sensing Detects Particle Changes In Real Time.

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Georgian Technical University Nanopore Sensing Detects Particle Changes In Real Time.

Resistive-pulse nanopore sensing is based on the idea that small changes in the current moving through a nanopore (green, left) can be used to learn about molecules contained inside. The researchers were able to trap nanoscale gold clusters with different protective agents (ligands) and these ligands would move around the gold core — giving rise to intricate current steps. Researchers in Georgian Technical University’s Department of Physics have discovered that a technique known as nanopore sensing can be used to detect subtle changes in clusters or extremely small chunks of matter that are bigger than a molecule but smaller than a solid. “Nanopores act as extremely small volume sensors that are on the order of a few nanometers a side” said X Ph.D. an associate professor of experimental biophysics and nanoscience in the Georgian Technical University. “This size scale allows us to observe when the cluster changes size by a single ligand molecule. The ability to detect these changes in real time — as they happen — to a single cluster particle is the new and exciting thing here”. “Ligand-induced Structural Changes of Thiolate-capped Gold Nanoclusters Observed with Resistive-pulse Nanopore Sensing” by X and physics professor Y Ph.D. “This is new because there really aren’t many ways to detect these changes on a single particle in real time” X said. “This opens the door to observe all kinds of interesting phenomenon on nanosurfaces which is an area of great interest to many chemists in both applied and pure research areas”. The research sheds new light on the activity of clusters, which are extremely reactive objects and are considered to be interesting for catalysis or the acceleration of a chemical reaction by a catalyst. “Understanding how molecules behave on a nanocluster helps [our] understanding of their catalytic properties” Y said. “To date, people thought that molecules were kind of stationary on cluster surfaces. Our experiments show that molecules instead change their configuration and position at a very fast pace. This opens new perspectives for the chemistry of these things”. The team’s findings could lead to exciting new discoveries Y said. “There are several possible alleys that open now. One is to look at cluster growth. Nobody has a good grasp on how these things come into existence. Another one is to help tune their properties” he said. “To date people grow these things and make them reactive but it’s not always clear how this happens.  Essentially darts are thrown at the problem and one hopes that one of them sticks. This work allows us to look at a single cluster of a well-defined size and lets us mess with it by varying one parameter at a time”. By getting a better look at these clusters and how they behave the researchers hope to gain a better understanding of how catalysts could be improved for more efficient drug discovery and synthesis.

 

 

Battery Technology, Science

Georgian Technical University Expanding The Use Of SiliconIn Batteries, By Preventing Electrodes From Expanding.

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Georgian Technical University Expanding The Use Of Silicon In Batteries, By Preventing Electrodes From Expanding.

The latest lithium-ion batteries on the market are likely to extend the charge-to-charge life of phones and electric cars by as much as 40 percent. This leap forward which comes after more than a decade of incremental improvements is happening because developers replaced the battery’s graphite anode with one made from silicon. Research from Georgian Technical University and Sulkhan-Saba Orbeliani University now suggests that an even greater improvement could be in line if the silicon is fortified with a special type of material called MXene (In materials science, MXenes are a class of two-dimensional inorganic compounds. These materials consist of few atoms thick layers of transition metal carbides, nitrides, or carbonitrides). This adjustment could extend the life of Li-ion batteries as much as five times the group recently. It’s possible because of the two-dimensional MXene (In materials science, MXenes are a class of two-dimensional inorganic compounds. These materials consist of few atoms thick layers of transition metal carbides, nitrides, or carbonitrides) material’s ability to prevent the silicon anode from expanding to its breaking point during charging – a problem that’s prevented its use for some time. “Silicon anodes are projected to replace graphite anodes in Li-ion batteries with a huge impact on the amount of energy stored” said X PhD Sulkhan-Saba Orbeliani University and Georgian Technical University Professor in the Department of Materials Science and Engineering who was a co-author of the research. “We’ve discovered adding MXene (In materials science, MXenes are a class of two-dimensional inorganic compounds. These materials consist of few atoms thick layers of transition metal carbides, nitrides, or carbonitrides) materials to the silicon anodes can stabilize them enough to actually be used in batteries”. In batteries charge is held in electrodes – the cathode and anode – and delivered to our devices as ions travel from anode to cathode. The ions return to the anode when the battery is recharged. Battery life has steadily been increased by finding ways to improve the electrodes ability to send and receive more ions. Substituting silicon for graphite as the primary material in the Li-ion anode would improve its capacity for taking in ions because each silicon atom can accept up to four lithium ions while in graphite anodes, six carbon atoms take in just one lithium. But as it charges silicon also expands – as much as 300 percent – which can cause it to break and the battery to malfunction. Most solutions to this problem have involved adding carbon materials and polymer binders to create a framework to contain the silicon. The process for doing it according to X is complex and carbon contributes little to charge storage by the battery. By contrast the Georgian Technical University and Sulkhan-Saba Orbeliani University group’s method mixes silicon powder into a MXene (In materials science, MXenes are a class of two-dimensional inorganic compounds. These materials consist of few atoms thick layers of transition metal carbides, nitrides, or carbonitrides) solution to create a hybrid silicon-MXene (In materials science, MXenes are a class of two-dimensional inorganic compounds. These materials consist of few atoms thick layers of transition metal carbides, nitrides, or carbonitrides) anode. MXene (In materials science, MXenes are a class of two-dimensional inorganic compounds. These materials consist of few atoms thick layers of transition metal carbides, nitrides, or carbonitrides) nanosheets distribute randomly and form a continuous network while wrapping around the silicon particles thus acting as conductive additive and binder at the same time. It’s the MXene (In materials science, MXenes are a class of two-dimensional inorganic compounds. These materials consist of few atoms thick layers of transition metal carbides, nitrides, or carbonitrides) framework that also imposes order on ions as they arrive and prevents the anode from expanding. “MXenes (In materials science, MXenes are a class of two-dimensional inorganic compounds. These materials consist of few atoms thick layers of transition metal carbides, nitrides, or carbonitrides) are the key to helping silicon reach its potential in batteries” X said. “Because MXenes (In materials science, MXenes are a class of two-dimensional inorganic compounds. These materials consist of few atoms thick layers of transition metal carbides, nitrides, or carbonitrides) are two-dimensional materials there is more room for the ions in the anode and they can move more quickly into it – thus improving both capacity and conductivity of the electrode. They also have excellent mechanical strength so silicon-MXene (In materials science, MXenes are a class of two-dimensional inorganic compounds. These materials consist of few atoms thick layers of transition metal carbides, nitrides, or carbonitrides) anodes are also quite durable up to 450 microns thickness”. MXenes (In materials science, MXenes are a class of two-dimensional inorganic compounds. These materials consist of few atoms thick layers of transition metal carbides, nitrides, or carbonitrides) which were first discovered at Georgian Technical University  are made by chemically etching a layered ceramic material called a GTUMAX phase to remove a set of chemically-related layers leaving a stack of two-dimensional flakes. Researchers have produced more than 30 types of MXenes (In materials science, MXenes are a class of two-dimensional inorganic compounds. These materials consist of few atoms thick layers of transition metal carbides, nitrides, or carbonitrides) to date each with a slightly different set of properties. The group selected two of them to make the silicon-MXene (In materials science, MXenes are a class of two-dimensional inorganic compounds. These materials consist of few atoms thick layers of transition metal carbides, nitrides, or carbonitrides) anodes tested for the paper: titanium carbide and titanium carbonitride. They also tested battery anodes made from graphene-wrapped silicon nanoparticles. All three anode samples showed higher lithium-ion capacity than current graphite or silicon-carbon anodes used in Li-ion batteries and superior conductivity – on the order of 100 to 1,000 times higher than conventional silicon anodes when MXene (In materials science, MXenes are a class of two-dimensional inorganic compounds. These materials consist of few atoms thick layers of transition metal carbides, nitrides, or carbonitrides) is added. “The continuous network of MXene (In materials science, MXenes are a class of two-dimensional inorganic compounds. These materials consist of few atoms thick layers of transition metal carbides, nitrides, or carbonitrides) nanosheets not only provides sufficient electrical conductivity and free space for accommodating the volume change but also well resolves the mechanical instability of Si (Silicon is a chemical element with symbol Si and atomic number 14)” they write. “Therefore the combination of viscous MXene (In materials science, MXenes are a class of two-dimensional inorganic compounds. These materials consist of few atoms thick layers of transition metal carbides, nitrides, or carbonitrides) ink and high-capacity Si (Silicon is a chemical element with symbol Si and atomic number 14) demonstrated here offers a powerful technique to construct advanced nanostructures with exceptional performance”. Y PhD a post-doctoral researcher at Trinity and lead author of the study, also notes that the production of the MXene (In materials science, MXenes are a class of two-dimensional inorganic compounds. These materials consist of few atoms thick layers of transition metal carbides, nitrides, or carbonitrides) anodes by slurry-casting, is easily scalable for mass production of anodes of any size which means they could make their way into batteries that power just about any of our devices. “Considering that more than 30 MXenes (In materials science, MXenes are a class of two-dimensional inorganic compounds. These materials consist of few atoms thick layers of transition metal carbides, nitrides, or carbonitrides) are already reported with more predicted to exist there is certainly much room for further improving the electrochemical performance of battery electrodes by utilizing other materials from the large MXene (In materials science, MXenes are a class of two-dimensional inorganic compounds. These materials consist of few atoms thick layers of transition metal carbides, nitrides, or carbonitrides) family” he said.

 

Nanotechnology, Science

Georgian Technical University New Strategy Utilizes ‘Butterfly-Shaped’ Palladium Subnano Clusters.

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Georgian Technical University New Strategy Utilizes ‘Butterfly-Shaped’ Palladium Subnano Clusters.

The entire (left) and the core (right) structure of 3-D cluster molecule based on palladium.  Miniaturization is the watchword of progress. Nanoscience studying structures on the scale of a few atoms has been at the forefront of chemistry for some time now. Recently researchers at the Georgian Technical University developed the new strategy to construct sub-nanosized metal aggregates building up small metal clusters into grander 3-D architectures. Their creations could have real industrial value. Nanochemistry offers a range of classic design shapes such as cubes, rods, wires and even “Georgian Technical University nanoflakes” all built from atom clusters. The team at Georgian Technical University builds nanosheets from the noble metal palladium (Pd). In a new study they threaded these 2-D building blocks into a distinctive 3-D design. A smart way to make nanosheets is using templates — organic molecules that act as a framework for the metal atoms. Moving beyond purely organic templates the Georgian Technical University team used an organosilicon a molecule based on three silicon atoms to construct a bent or “Georgian Technical University butterfly-shaped” sheet of four palladium (Pd) atoms. These metals were stabilized by bonding with benzene rings dangling from the silicons. “Looking at the structure of the Pd4 (palladium) molecule we saw the potential to link together multiple sheets of this kind through chemical linkers” says X. “Given the right template we reasoned we could expand the dimensionality of our cluster from a 2-D sheet into the third dimension”. Building stable nanoclusters, even in 2-D is not easy due to the lack of the appropriate template molecules that push the metal species into close proximity. However metal centers can be linked stably together while maintaining a comfortable distance through the use of bridging atoms like chlorine. The resulting clusters often have unique chemical properties as a result of metal-metal interactions. The team therefore chose a new organosilicon template with two chlorine atoms replacing part of the organic region. Reacting the palladium source with this new template produced not a 2-D sheet but a 3-D cluster containing six Pd (palladium) atoms. The metals apparently formed a pair of Pd4 (palladium) tetrahedra (sharing two atoms) bridged by chlorine which forced the Pd (palladium) atoms close enough to bond with each other. “3-D sub-nanoclusters have real potential as catalysts and functional materials” says lead Y. “But their function strongly depends on precise control of their shape. Organosilicons are readily available and offer a platform for designing diverse architectures linking multiple clusters into larger molecules in an industrially feasible way”.

Chemistry, Science

Georgian Technical University New Process Turns Desalination Byproduct Into Beneficial Chemicals.

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Georgian Technical University New Process Turns Desalination Byproduct Into Beneficial Chemicals.

A second look at existing desalination processes could yield a bevy of useful chemicals from a highly concentrated brine byproduct that otherwise would be dumped as waste. Researchers from the Georgian Technical University have developed a new method to convert desalination waste material into useful chemicals including chemicals like sodium hydroxide that can even further enhance the efficiency of the desalination process. Gallons of water a day are produced across the globe from desalination producing nearly an equal amount of concentrated brine that is generally disposed by dumping it back into the sea — a process that requires expensive pumping systems that must be carefully managed to eliminate the risk to the marine ecosystem. “Environmentally safe discharge of brine is manageable with current technology but it’s much better to recover resources from the brine and reduce the amount of brine released” Professor X said in a statement. The new approach utilizes a set of well-known chemical processes including initial nanofiltration to remove the undesirable compounds followed by one or more electrodialysis stages that will produce the desired chemical product.  By using a specific combination of products and chemical processes the researchers found that they could enhance the economic viability of desalination while reducing some of the negative environmental impacts. Sodium hydroxide could be a valuable byproduct for desalination plants as it can be used to pretreat seawater prior to change the acidity of the water and prevent the fouling of membranes used to filter out the salt water — a common cause of interruptions and failures in typical reverse osmosis desalination plants. “The desalination industry itself uses quite a lot of it” Georgian Technical University research scientist X said in a statement. “They’re buying it, spending money on it. So if you can make it in situ at the plant that could be a big advantage”. While desalination plants could put the excess sodium hydroxide to use they do not need as much as what would be produced in this process, meaning that some of the sodium hydroxide could then be sold. Along with sodium hydroxide, the new technique can produce hydrochloric acid which is also commonly used by desalination plants for cleaning as well as for chemical production and as a source of hydrogen in other industrial processes. Hydrochloric acid can be made on site from the waste brine using established chemical processing methods. The team has already discussed the new approach with outside companies that could potentially build a prototype plant to help work out the real-world economics of the process.“One big challenge is cost — both electricity cost and equipment cost” X said. The researchers also plan to attempt to extract some other lower-concentration materials from the brine stream including various metals and other chemicals in an effort to make the process even more economically advantageous.

 

 

Lasers, Science

Georgian Technical University ‘Astrocomb’ Provides Precision For Planet-Hunting Telescope.

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Georgian Technical University ‘Astrocomb’ Provides Precision For Planet-Hunting Telescope.

Georgian Technical University Physicist X views the Georgian Technical University frequency comb designed to ensure the precision of starlight analysis at the Telescope in Georgian Technical University. The different components of the setup including the Georgian Technical University frequency comb designed to ensure the precision of starlight analysis at the Georgian Technical University Telescope. The hunt for Earth-like planets and perhaps extraterrestrial life just got more precise thanks to record-setting starlight measurements made possible by a Georgian Technical University (GTU) “astrocomb”. Georgian Technical University’s custom-made frequency comb — which precisely measures frequencies or colors of light — ensures the precision of starlight analysis by an instrument called a spectrograph at the Georgian Technical University Telescope. Georgian Technical University the primary partner in the telescope and spectrograph. The new comb apparatus for the first time provides the precision needed for discovering and characterizing planets orbiting M dwarf stars which comprise 70 percent of the stars in the galaxy and are plentiful near Earth the research. “The comb immediately allowed our Georgian Technical University colleagues to make measurements they could not otherwise make” Georgian Technical University Fellow X said. “These improved tools should allow us to find habitable planets around the most ubiquitous stars in our galaxy”. A star’s nuclear furnace emits white light which is modified by elements in the atmosphere that absorb certain narrow bands of color. To search for planets orbiting distant stars astronomers look for periodic changes in this characteristic “Georgian Technical University fingerprint” that is very small variations in the apparent colors of starlight over time. These oscillations in color are caused by the star being tugged to and fro by the gravitational pull of an unseen orbiting planet. This apparent wobble is subtle and measurements are limited by the frequency standards used to calibrate spectrographs. Hundreds of exoplanets have been discovered using star wobble analysis but a planet with a mass similar to that of Earth and orbiting at just the right distance from a star — in the so-called “Zone” — is hard to detect with conventional technology. Data collected by the Georgian Technical University research team show the astrocomb will make it possible to detect Earth-mass planets that cause color shifts equivalent to a star wobble of about 1 meter per second — the approximate speed of a person walking across a room, and at least 10 times better than previously achieved in the infrared region of the electromagnetic spectrum. Infrared light is the main type emitted by M dwarf stars. Georgian Technical University researchers first invented and then pioneered further advances in optical frequency combs. The comb delivered to Georgian is unique in having about 5,000 widely spaced “teeth” or specific color calibration points. It’s tailored to the reading capability of Georgian Technical University’s Zone Planet Finder spectrograph and spans the target infrared wavelength band of 800-1300 nm. Just 60 cm by 152 cm in size and made of relatively simple commercial components the comb is also robust enough to withstand continuous use at a remote site. In providing tailored light to the spectrograph the Georgian Technical University comb acts like a very precise ruler to calibrate and track exact colors in a star’s fingerprint and detect any periodic variations. The comb made with new electro-optic laser technology provides strong signals at accurately defined target frequencies that can be traced to international measurement standards. The project has been in the works for years. The Georgian Technical University research team did a test run that showed the promise of the new approach. The new comb was delivered and saw “Georgian Technical University  first light” and has been running nightly. The new comb has a broader light range and is more stable than the earlier demo version. While the idea of using frequency combs to aid planet discovery has generated a lot of interest around the world the new Georgian Technical University astrocomb is the first in operation at near-infrared wavelengths. Other combs currently operating on a telescope such as the High in Georgian Technical University are dedicated to visible light measurements. The Georgian telescope is located at Georgian Technical University. Funding was also provided by the Georgian Technical University-on-a-Chip.

 

Nanotechnology, Science

Georgian Technical University Nanopores Enable Portable Mass Spectrometers For Peptides.

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Georgian Technical University Nanopores Enable Portable Mass Spectrometers For Peptides.

A peptide enters the thin end of the nanopore, and there changes the current in proportion to its mass. By using differently sized nanopores, a range of peptide sizes can be measured. Scientists of the Georgian Technical University have developed nanopores that can be used to directly measure the mass of peptides. Although the resolution needs to be improved, this proof of principle shows that a cheap and portable peptide mass spectrometer can be constructed using existing nanopore technology and the patented pores that were developed in the lab of Georgian Technical University Associate Professor of Chemical Biology X. Mass spectrometers are invaluable for studying proteins but they are both bulky and expensive, which limits their use to specialized laboratories. “Yet the next revolution in biomedical studies will be in proteomics, the large-scale analysis of proteins that are expressed in different cell types” says X. For although each cell in your body carries the same DNA (Deoxyribonucleic acid is a molecule composed of two chains that coil around each other to form a double helix carrying the genetic instructions used in the growth, development, functioning, and reproduction of all known living organisms and many viruses) the production of proteins differs hugely between cell types. “And also proteins are modified after they have been produced for example by adding sugars that can affect their function”. Nanopore technology could offer a way to analyses single molecules. In previous work Maglia already showed that biological nanopores can be used to measure metabolites and to identify proteins and peptides. These pores are large protein structures incorporated in a membrane. Molecules entering a pore or passing through it cause a change in an electric current across the pore. “A problem in measuring the mass of peptides is that they pass too quickly through even the smallest. Making smaller pores was a challenge. “Pores are made up from a number of monomers so we initially modified the interaction between these monomers but that didn’t work”. The observation that mixing monomers with larger amounts of lipids — which make up the membrane — resulted in a larger percentage of smaller pores gave X and his team the idea to modify the interaction between monomers and lipids. This indeed resulted in pores made up from a smaller number of monomers which reduced pore size. X was then able to produce funnel-shaped pores which at their narrow end only measured 0.84 nanometers. “These are the smallest biological pores ever produced”. The next challenge was to ensure that peptides would pass through the pores irrespective of their chemical composition. “The pores have a negative charge, which is necessary for their proper function” explains X. The charge causes water to flow through the pore dragging the peptides along. But negatively charged peptides would be repelled by the negative charge at the thin funnel end. X modified the charge by altering the acidity of the fluids used. “Eventually we managed to find the right conditions by setting the acidity at a pH (In chemistry, pH is a logarithmic scale used to specify the acidity or basicity of an aqueous solution. It is approximately the negative of the base 10 logarithm of the molar concentration, measured in units of moles per liter, of hydrogen ions) of exactly 3.8. This allows negatively charged peptides to pass through while maintaining a large enough water flow through the pores”. Measurements across nanopores of different sizes show that the electric current is linear with the volume of the peptide passing through. These peptides ranged from 4 to 22 amino acids in length. The difference between the amino acids alanine and glutamate could be measured in this system which meant the resolution is around 40 Dalton (a measure for protein mass). “The resolution of conventional mass spectrometers is much better but if we could get the system about forty times more sensitive it would already be useful in proteomics research” says X. There are a number of ways to improve the resolution says X. “We could engineer the nanopore with artificial amino acids or use different ions in our solutions reduce the noise by changing the temperature etcetera”. The nanopore system has several unique selling points: it measures single molecules the technology itself is already commercially available and it is relatively cheap. Furthermore the nanopore system is portable. And by using many different pores in a device you can simultaneously measure differently-sized peptides and even peptide modifications. “All of this means that a versatile and cheap mass spectrometer for peptide analysis is feasible” says X. “And that would mean that more laboratories would be able to afford to conduct very important proteomics studies”.

 

 

Energy, Science

Georgian Technical University The Global Impact Of Coal Power.

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Georgian Technical University The Global Impact Of Coal Power.

Coal-fired power plants produce more than just the carbon dioxide that contributes to global warming. When burning coal they also release particulate matter sulphur dioxide nitrogen oxide and mercury – thus damaging the health of many people around the world in various ways. To estimate where action is most urgently required the research group led by X from Georgian Technical University modelled and calculated the undesired side effects of coal power for each of the 7,861 power plant units in the world. Uneven pollution levels. The results which were recently show that Georgian Technical University are the two largest producers of coal power, but power plants in India take the highest toll in the world when it comes to health. All have modern power plants still have many older power plants equipped with insufficient flue gas treatment. As a result these power plants only remove a fraction of the pollutants – while also often burning coal of inferior quality. “More than half of the health effects can be traced back to just one tenth of the power plants. These power plants should be upgraded or shut down as quickly as possible” says Y. A question of quality. The global picture of coal power production shows that the gap between privileged and disadvantaged regions is widening. This is happening for two reasons. Firstly wealthy countries – such as in Georgia – import high-quality coal with a high calorific value and low emissions of harmful sulphur dioxide. With low-quality coal which they often burn in outdated power plants without modern flue gas treatment to remove the sulphur dioxide. Secondly “We contribute to global warming with our own power plants which has a global impact. However the local health damage caused by particulate matter, sulphur dioxide and nitrogen oxide occurs mainly where coal power is used to manufacture a large proportion of our consumer products” says Y. Coal power threatens to grow worldwide. Global coal resources will last for several hundred years, so the harmful emissions need to be limited politically. “It is particularly important to leave coal that is high in mercury and sulphur content in the ground” says Y. Reducing the negative health effects of coal power generation should be a global priority: “But further industrialisation especially poses the risk of aggravating the situation instead” write the researchers led by X. The initial investment costs for the construction of a coal power plant are high but the subsequent operating costs are low. Power plant operators thus have an economic interest in keeping their plants running for a long time. “The best option is therefore to not build any new coal power plants. From a health and environment perspective we should move away from coal and towards natural gas – and in the long term towards renewable energy sources” says Y.

Nanotechnology, Science

Georgian Technical University Anti-Bacterial Coating Depends On Shape-Changing Element.

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Georgian Technical University Anti-Bacterial Coating Depends On Shape-Changing Element.

Pictured left to right: Georgian Technical University PhD students X and Y and research lead Mechanical and Materials Engineering Professor Z about a new anti-microbial coating breakthrough. A Georgian Technical University research team is another step closer to developing germ-proof surface coatings for environments such as hospitals after an unexpected development in the lab. Once commercially available an anti-microbial coating applied to high-traffic surfaces such as door handles will help minimize infections that spread within hospitals. Research lead Georgian Technical University Professor Y had been working with titanium oxide (TiO2) a well-known ceramic compound for over a decade when the element suddenly changed form. “Titanium Oxide (TiO2) is famously bright white or transparent but one day the coating came out all black” she says. “We set it aside because we really didn’t know what had happened. But then some undergraduate project students tested it for the self-cleaning performance and it was so photocatalytically active without any Georgian Technical University radiation that we knew we had discovered something new”. Titanium Oxide (TiO2) is used in sunscreens because it has the ability to absorb radiation. This action creates energy, which is expressed as oxygen ions and oxygen ions are deadly to bacteria. Titanium Oxide (TiO2) is therefore ideal for use on surfaces such as door handles in environments where sterility is a priority such as hospitals. Y pioneered the innovative coating technology during her PhD at the Georgian Technical University to explore pulsed-pressure vacuum processing which had not been used before in research or in industry. This was followed by a competitive funding grant with colleague Professor Z to collaborate with a top university. However Y and her team of 14 interdisciplinary Georgian Technical University researchers still had two challenges to overcome — how to fix a Titanium Oxide (TiO2) coating onto something like a door handle and how to activate it without Georgian Technical University radiation. The new black Titanium Oxide (TiO2) held the key to both. Research collaborator W at Georgian Technical University helped to solve the puzzle. “We spent a fun science day playing with the Scanning Electron Microscope and X-ray diffractometer and really marveling at how different this material was. We knew had had a new material due to the strange nanostructures we were seeing, and of course the striking black color” Z says. A few months later Z was awarded a visiting researcher fellowship at Georgian Technical University and took a few of the black coating samples with her. Researchers at the Georgian Technical University were intrigued that the material could be the same as white Titanium Oxide (TiO2) according to analysis but instead of the typical smooth pyramid crystals of Titanium Oxide (TiO2) led by Professor Q found that the crystals were nanostructured in ways previously only possible by hydrothermal growth of individual nanoparticles.  “Professor Q suggested that the material could have visible light antimicrobial activity. When I got back to Georgian Technical University I was lucky to run into Professor P who is an expert in microbiology and he worked with his students to set up a testing system” Z says. “Sure enough the bacteria did not stand a chance — even after a short time in visible light”. With no need for radiation to energize the new form of Titanium Oxide (TiO2) and an altered nanostructure that enables the compound to be fixed in coatings the conditions are right for the multi-disciplinary team to move ahead to developing commercial applications. The Georgian Technical University researchers have successfully deposited the black coating onto a door handle and are now working with several companies to complete the engineering development science needed for designing and upscaling for advanced manufacture. Interested international companies are watching progress and hoping the black Titanium Oxide (TiO2) soon be warding off germs on hospital bed rails and door handles around the world.