#MolecularFoundry; #LawrenceBerkeleyNationalLaboratory; #nanoribbons
#electromagneticradiation; #NERSC; #nano-geometries,
Toronto, Apr 30 (Canadian-Media): When scientists are trying to make things better, they will often turn to a standard rule and try to disprove or disrupt it, United States' Lawrence Berkeley National Laboratory researchers said.
Image Credit: Lawrence Berkeley National Laboratory
A consortium of researchers using the unique Molecular Foundry at Lawrence Berkeley National Laboratory (Berkeley Lab) set out to do just that with Planck's Law.
Planck's Law, which forms the basis of quantum theory, states that electromagnetic radiation from heated bodies is distributed over a wide range of wavelengths and wide range of angles.
However, Max Planck himself noted that the emitting energy distribution would deviate significantly from his law if the characteristic size of the emitting object is smaller than the thermal wavelength (about 10 micrometers at room temperature). With the advent of micro- and nanotechnology, it is easy to fabricate materials where Planck's Law will not hold.
The researchers set out to determine the deviation from Planck's Law in order to understand this impact on technologies based on nano- and micro-structured geometries. Imagine a thermal storage material that converts electricity to heat and then radiates it to a photovoltaic cell to get the electricity back when desired. The radiative emitter from the thermal storage could be made from nanostructures to maximize the performance.
Another example is in the area of high temperature nano-geometry-based thermoelectrics, where high temperature waste heat is converted to electricity. It is important to understand the radiation from these nanoscale features, as radiation is the dominant source of heat leakage at high temperatures and will lead to reduction in heat-to-electricity conversion efficiency.
Research like this is what U.S. national laboratories focus on. Researchers ask the questions and do the experiments that industry may not be able to support early on.
Scientific user facilities such as the Molecular Foundry also aid in this type of research. The Molecular Foundry is a Department of Energy (DOE)-funded nanoscience research entity that provides users from around the world with access to cutting-edge expertise, instrumentation and modeling tools in a collaborative, multidisciplinary environment.
In this case, researchers used the radiation models available in the Molecular Foundry to model the thermal radiation from rectangular nanoribbons of silica glass, a polar dielectric material. The modeling was performed using supercomputers in the National Energy Research Scientific Computing Center (NERSC), another DOE user facility located at Berkeley Lab. The experiments were conducted by researchers at University of California, San Diego.
"Nobody has explored the relative behavior of nano-geometries, particularly anisotropic nano-geometries—nanostructures that are rectangular in cross-section—in this way," said Ravi Prasher, one of the researchers.
Practical applications for this early-stage energy conversion are important for many renewable energy applications, such as concentrated solar electricity production, water desalination, thermochemical reactions, water heating, and thermal storage.
The publication, "Far-field coherent thermal emission from polaritonic resonance in individual anisotropic nanoribbons," was published in Nature Communications in March 2019.
#detectionofhatespeech; #fakenews; #StaViCTA; #KostiantynKucher; #academicresearch; #businessintelligence; #socialmediatexts; #journalism; #artificialintelligence
Sweden, Apr 29 (Canadian-Media): How can you find and make sense of opinions and emotions in the vast amount of texts in social media? Kostiantyn Kucher's research helps visualise for instance public opinions on political issues in tweets over time. In the future, analysis and visualisation of sentiment and stance could contribute to such tasks as detection of hate speech and fake news, Sweden's Linnaeus University research said.
Our society relies on language and text to express our thoughts, exchange opinions, and gain new knowledge. But with so much text data being produced nowadays, in particular in social media, it's impossible to read everything manually. In his dissertation in computer science at Linnaeus University, Kostiantyn Kucher has looked for a solution to this problem.
"My research shows how one can investigate and make sense of opinions and emotions in collections of text data by combining computerised text mining methods and interactive visual representations, that is, special types of charts and graphs," says Kostiantyn Kucher.
As part of a research project called StaViCTA, Kostiantyn and colleagues have provided online survey browsers that are now used by researchers, practitioners, and students interested in text visualisation (http://textvis.lnu.se and http://sentimentvis.lnu.se). They have designed and implemented multiple visual analytics approaches that have helped their collaborators in linguistics and computational linguistics in their research on stance analysis.
The approaches presented in the dissertation can be applied in academic research, business intelligence, social media monitoring, and journalism. Besides social media texts, these approaches can also be used to visualise stance in books and business reports, for instance.
"In the future, analysis and visualisation of sentiment and stance could contribute to such tasks as detection of hate speech and fake news, improvement and adaptation of graphical user interfaces in software and web applications, and visual representation of the models used by artificial intelligence agents," concludes Kostiantyn Kucher.
Jerusalem, Apr 17 (Canadian-Media): In a major medical breakthrough, Tel Aviv University researchers have "printed" the world's first 3D vascularised engineered heart using a patient's own cells and biological materials, media reports said.
Image credit: Tel Aviv University website
"This is the first time anyone anywhere has successfully engineered and printed an entire heart replete with cells, blood vessels, ventricles and chambers," says Prof. Tal Dvir of TAU's School of Molecular Cell Biology and Biotechnology, Department of Materials Science and Engineering, Center for Nanoscience and Nanotechnology and Sagol Center for Regenerative Biotechnology, who led the research for the study.
"This heart is made from human cells and patient-specific biological materials. In our process these materials serve as the bioinks, substances made of sugars and proteins that can be used for 3D printing of complex tissue models," Dvir says. "People have managed to 3D-print the structure of a heart in the past, but not with cells or with blood vessels. Our results demonstrate the potential of our approach for engineering personalized tissue and organ replacement in the future."
"At this stage, our 3D heart is small, the size of a rabbit's heart," explains Dvir. "But larger human hearts require the same technology."
"The biocompatibility of engineered materials is crucial to eliminating the risk of implant rejection, which jeopardizes the success of such treatments," Prof. Dvir says. "Ideally, the biomaterial should possess the same biochemical, mechanical and topographical properties of the patient's own tissues. Here, we can report a simple approach to 3D-printed thick, vascularized and perfusable cardiac tissues that completely match the immunological, cellular, biochemical and anatomical properties of the patient."
The researchers are now planning on culturing the printed hearts in the lab and "teaching them to behave" like hearts, Prof. Dvir says. They then plan to transplant the 3D-printed heart in animal models.
"We need to develop the printed heart further," he concludes. "The cells need to form a pumping ability; they can currently contract, but we need them to work together. Our hope is that we will succeed and prove our method's efficacy and usefulness.
"Maybe, in ten years, there will be organ printers in the finest hospitals around the world, and these procedures will be conducted routinely."
(Reporting by Asha Bajaj)
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